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The Major Quake Zones

Quick Links

Graphs of Comparative Activity Between Zones

 

 

 


  Quakes By Zone |     Zones By %    |    Pac Rim By %   |   Zone Trends

Storyboard Topics

Introduction  |  Major Findings  |  Table of Contents

Compression Zones   |  Expansion Rifts  |  Zone Definitions

Motions of the Tectonic Plates

 

World Distribution Earthquakes Magnitude 1 & Greater 1991-1996

This composite chart succinctly shows the edges of the major tectonic plates,
and the most active zones of earthquakes and volcanoes.

xxx edit: source this USGS - NEIC Map

 
The next chart reduces the clutter in the first one and focuses the mind precisely on the most dangerous tectonic zones of the Earth. With the exception of the North Atlantic which is just about the most active quake zone but which has not produced  a quake over 6.9 since recording began, these 7+ quakes reveal approximately where the surface of the Earth is most active with all forms of tectonic forces and changes, ranging from quakes of all sizes, to uplifting, downwarping, volcanism, and deep crustal slippage.  If current trends in tectonic activity continue in their current pattern of long-term acceleration, all the zones with circles will begin, at various times during Century 21, to suffer increasing destruction of human habitat and out-migration.
 
World Distribution of Class 7+ Quakes 1975-2007
USGS - NEIC Map As Of July 2007
local file name: NEIC_world_map_7+_quakes_1975-2006.GIF
 

Abstract

The graphs for the major tectonic zones are arranged in two layers.  One layer is composed only of graphs of Class 4+ quakes from 1973-2007. These graphs, with commentary, are housed in the "Storyboard For Compression Zone 4+ Quakes" which is located on the webpage for the Compression Zones, which is where most of the quakes 4+ occur.  A second, deeper layer is composed of several graphs each for several of the major zones.  Special database models were created for selected areas to analyze earthquake activity for Classes 2.5+, in some cases for quakes as small as 2.00.  Because of various issues, most especially PC software limitations, generally these databases display a smaller time frame:  1991-2007.

Reference to Quake Zone Definitions:  See "Definitions For Expansion Zones" or see "Definitions For Compression Zones"

Major Observations

For Class 4+ Zone Quakes:  read here



Table of Contents

As with the general Earthquake Gallery Index, you can click on any of the iconic graphs or pix below to expand it up to its full size.  Some are so large horizontally that the browser will shrink them to fit in one view window.  This will result in an unreadable graph. Simply click on the shrunken graph or map to tell the browser to expand it back to full size. All compressed images in the Earthquake Gallery work the same way.  The images which give you only blurry lines are graphs which are very wide on the horizontal scale to provide monthly or daily details.   The titles in the text block to the right of the compressed graphs are linked to a section in a web page which explains the graph and offers observations and analysis of what you are seeing.  Most of the Earthquake Gallery unfolds this way.  You can quickly browse through the miniatures to find items which you want to read about.

World Distribution Class 1 & Greater Quakes 1991-1996
USGS - NEIC Map
top of this web page

 

World Distribution Class 7+ Quakes 1975-2007
USGS - NEIC Map As Of July 2007
top of this web page

 

 

Abstract

 

Major Observations

Storyboard For The Major Tectonic Zones

Introduction

Its All About Shape-Shifting

Shape-Shifting Begins With The Great Rift

Defining The Tectonic Activity Zones

 

 

Digital Elevation Map From NOAA
This doesn't really belong on this page but this is where it lives at the moment. Go to the panel to get the link for a gigantic wall sized elevation map for seeing where all the danger zones are for Global Warming sea level rise and tectonic activity.

Modeling The Tectonic Activity Zones

The Use of Google

The Use Of NOAA'S World Surface Model

NOAA ETOPO2v2 Global Gridded 2-minute Database
Two-minute gridded global relief  MAPS for both ocean and land areas are available in the ETOPO2v2 (2006) database.

The Use of Polygon Parameters and Map Coordinates

Conventions of Numbers, Lats, & Longs

Model Specifications

Definitions For The Expansion Rifts
 

Antarctic Rifts - Definitions

Antarctica-Bharati  Definition

Antarctica-Pacific  Definition

Antarctica-Atlantic Zone of Ambiguity

 

Arctic-Atlantic Rifts -  Definitions

Arctic Definition
This is a huge PDF file of a very high quality large image

 

 

 

 

North Atlantic Definition

 

 

 

 

South Atlantic Definition

 

 

 

 

East Pacific Rift Definition

 

 

 

 

Definitions For The Compression Zones

Eurasian Compression Zones

Eurasia

 

 

 

 

East Bharati (East Indian Plate)

 

 

 

 

Aleutians-Alaska

 

 

 

 

Japan & East Asia

 

 

 

 

Western Pacific  (Philippines Plate)

 

 

 

 

Australia & New Zealand

Africa

 

 

 

 

Motions Of The Tectonic Plates
This section is presented in the Storyboard of Vortex Tectonics.  the items are included here as a sort of cross-reference.

go to Age of the Ocean Floor poster flier.The Expansion Rifts & Age Of The Ocean Plates

 

 

go to Measured & Estimated Seafloor Topography poster flier.Topographic Map Of Ocean Floor

 

 

How A Subduction Zone Works
The Puerto Rico Trench

Ocean Sediments - Another Clue To The Mystery Of Tectonic Motion

 

 

 

Comparative Activity Charts For The Major Zones

World Quakes 4+ Totals Distributed By Tectonic Zones 1973-2006
portrait by MWM 2007;
model source: ANSS Composite Database; world_quake_summary.xls by MWM
quakes_world4+_zonetots_1973-2007.gif

World Quakes 4+ Percentage Distribution By Tectonic Zones 1973-2006
portrait by MWM 2007;
model source:  ANSS Composite Catalog; world_quake_summary.xls by MWM
quakes_world4+_zone_percents_1973-2007.gif

 

Pacific Rim Quakes 4+ Percentage Distribution By Tectonic Zones 1973-2006
portrait by MWM 2007;
model source:  ANSS Composite Catalog; world_quake_summary.xls by MWM
quakes_world4+_Rim_zone_percents_1973-2007.gif

 

Comparative Trends

Comparative Trends In The Major Tectonic Zones
portrait by MWM
model source:  ANSS Composite Catalog; world_quake_summary.xls by MWM
quakes4+_compare_trends_majorzones_1973-2007

 


Charts & Storyboard Panels For Each Major Tectonic Zone

This list provides links to the individual storyboard webpages for each Major Tectonic Zone.  Because of the great number of images and graphs, the gallery inventory is not displayed here.  Instead they are listed and displayed on separate web pages, either on "Great Rift Expansion Zones" or on "Compression Zones".  Here is the whole systems outline:

Great Rift Expansion Zones

Atlantic (including Arctic) 1973-2007

Atlantic Great Rift 4+ Total 1973-2007
Incorporates the Arctic Ocean, Norwegian Sea, North Atlantic, and South Atlantic

Artic 4+ 1973-2007

North Atlantic 2+ 1973-2007

South Atlantic 4+ 1973-2007

East Pacific 1973-2007

Bharati (Indian Ocean) 1973-2007

Antarctica

Antarctica - All Expansion Rifts (nearly all)

Antarctica Rifts - Bharati Portion 1973-2007

Antarctica Rifts - Pacific Portion 1973-2007


 


Compression Zones 4+ Quakes Only

Storyboard For Quakes 4+ In Eurasia, South Pacific, & Western Hemisphere

Compression Zones - All Quakes

Africa - relatively little recorded data

Eurasian Zones

Eurasia 1973-2007

East Bharati 1973-2007

Western Arc Pacific Rim
(from the North to the South)

Western Arc Pacific Rim 1973-2007

Aleutians-Alaska 2+ 1973-2007

Japan & East Asia 1973-2007

Australia & New Zealand 4+ Only

Western Hemisphere Zones

North America Totals 4+ Only

Aleutians-Alaska 2+ 1973-2007

Eastern North America 2+ 1973-2007

Southern California 2+ 1932-2007
Multiple Charts & Storyboard

Western North America 2+ 1973-2007

Central America - The Carib Plate 2+ 1973-2007

South America 2+ 1973-2007

Storyboard For The Major Tectonic Zones

 

Introduction

There are many types of quakes and for most of them the key to what they are is location, location, location.   Fortunately, most such technicalities are irrelevant for the Earth Changes Gallery.  We are far more interested here in the fact that, for the most part, the major quake zones define the boundaries of the major tectonic plates of the Earth.  As they move against each other, either by sliding past each other or under or over each other, or away from each other, the tectonic plates generate quakes.  Thus, when we examine earthquakes, mostly we are examining motion in the tectonic plates.

Accordingly this part of the Earth Changes Gallery is organized primarily around two major types of tectonic locations: 

  1. in the oceans where the expansion rifts are pushing the tectonic plates and continents apart, and
     

  2. the resulting compression zones where the leading edges of the slowly moving tectonic plates meet their opposites and cause the earth to break, quake, and deform while uplifting or down-warping the Earth at their edges.

These two different types of zones are very easy to see in the two charts at the top of this web page.  The first chart shows all quakes for a five year period of magnitude 4.5+.  As can be seen quake activity is fairly well defined along certain linear zones.  The expansion rifts in the oceans can be seen in the long chains which "snake" through the oceans.  Notice that they are all connected.  The compression zones are easiest to spot in the second chart which displays only magnitude 7+ quakes.  For reasons not explained, the compression zones have more violent quakes than the expansion zones.  There are almost no 7+ quakes in the oceans, except around Australia. 

Is Australia  an exception?  No.  For the most part Australia is a low-lying tectonic plate which is half underwater.  For reasons not presently understood, it has not been uplifted with high plateaus like all the other continents.  Thus the compression zones at its edges appear to be in the middle of the ocean.

What about the activity in Eurasia along the Himalayas and across the Middle East?  Are these compression zones at the leading edge of motion for Eurasia equivalent to the Western Americas?  Yes.  Eurasia is so large, its southern edge is colliding with Africa, the Arabian Plate, theIndian Plate, and the Australian Plate.  Thus you see a long belt of horizontal activity from Nepal to the Aegean Sea.  Five different tectonic plates are involved, the dynamics for each are somewhat different, and the results vary widely, making the entire zone very complex indeed.  Since the Arabian Plate is perhaps best handled as a fragment of the African Plate, it is not discussed as a distinct object in the Gallery.

Cycle back and forth between the two charts by clicking on them alternatively.  Look at the various parts.  1. first chart 2. second chart   Get a sharper image in your mind of where the main compression zones are and where the main expansion zones are.

It's All About Shape-Shifting

In essence, the quest for this Gallery and Vortex Tectonics in general is to find and examine how the Earth shifts its shape.  As the Great Rift, which bisects the oceans, slowly spreads apart and expands, millimeter by millimeter, centimeter by centimeter, month by month , the shape of the whole Earth must and demonstrably does change .  As the shape changes, the tectonic plates and continents move to create the world we live in. This "shape-shifting" is the primary source of the stress vectors which produce most quake activity.

Two primary vectors force the shape-shifting. One of course are the orbits of the Moon and the Sun.  As the Earth rotates daily under the Moon's slow 29 day orbit, vast tides in both the oceans and the Earth lift the atmosphere and surface of the Earth and pull it constantly towards the west, in the opposite direction of the the Earth's Spin.  The Sun adds and subtracts to this vector, depending upon the monthly phase location of the Moon.

The second vector is Earth's Wobble.  The Wobble is a 14 month cycle and a seven year cycle of constant change in the location of the poles of the Spin Axis.  During these cycles, the wobble expands and contracts in size.  These changes in the Wobble exert a significant regular influence on how and how much the Earth shifts its shape.  This influence is readily seen in many of the earthquake graphs.  Earthquake activity can often be seen to increase and decrease in tandem with the rhythm of the Earth's expanding and contracting wobble spirals.

In fact, as will be seen in other portions of the Earth Changes Gallery, this "axis-shifting" and  "shape-shifting" is the source of most of the Earth Changes, including volcanism, Global Warming, and major biome shifts.  Behind both the "axis-shifting" and shape-shifting process, of course, is the "beat activity" of the cycles of change in the strength and orientation of the gravity vectors of the Sun and the Moon.   Their joint influence rules the surface of the Earth.

Acting on or technically beating with the slowly shifting Mass of the Earth/Moon System, the distributed Mass of the Solar System (the Sun and planets) are currently producing an acceleration in the rate of the progressive drift of the average location of the Earth's Spin Axis.  Exactly why this is an accelerating trend at this time is not understood.  But the FACT that it IS occurring is easy to observe and requires no stretch of the mind to conclude the perfectly obvious.

In other, more specific terms, we are living through a cosmically-driven trend of tectonic change in the Earth.  The accumulating rate of acceleration in the drift of the location of the Spin Axis  is driving the observable Global Trends in earthquake activity (four to fivefold during the past fifty years for activity at magnitude 2.5 or greater)  and volcanic activity (threefold during the past fifty years).  This increase in tectonic motion and heat release is in turn driving most climate change and Global Warming phenomenon.

For a discussion of the geophysics of how this works, see the Storyboard For The Earth's Wobble.  This remainder of the Earthquake Storyboard discusses only the processes of Rifting and Compression which directly produce earthquakes and volcanoes.

It Begins With The Great Rift

The key to the process lies in the Great Rift.  As it spreads, it cracks enough to allow magma to well up between the sides of the cracks and form  either "dikes" between the spreading sides, or vast oozes out over the ocean floor to build up vast "ridges".  Some portions of these magma ridges are greater in height than most of the continental mountains and they have become widely known by such names as "Mid-Atlantic" Ridge, or the "East Pacific Ridge", etc.  These place names allow us to find a specific zone but they often obscure the identity of these zones  as part of one vast, contiguous tectonic structure.  In fact the Great Rift is by the most significant geologic feature of Earth and it vastly overshadows all other details.  It is very sad that it is almost invisible to us.

All this cracking, spreading, and magma diking must be and is accompanied by earthquake activity.  The rate of this shape-shifting activity in various portions of the Earth should be definable by measuring the seismic signals of the Great Rift.  Unfortunately, the greater portions of the Great Rift are not monitored closely enough and thus the greater part of its quake activity is not recorded. 

This leaves us in great and appalling ignorance about the most fundamental geological dynamic on the Earth.  However, enough is being recorded in databases to allow us to learn a few basic things.  We may even be able to see a few important "clues" about how the shape shifting is occuring, in what directions the tectonic plates are really moving relative to each other, and how and when their motions are shaped within the cosmic matrix.

The Great Rift has been fairly well defined and thus it is possible to search and manipulate the quake databases to build a profile of their "movements".  Since the Great Rift is like a baseball seam, or as a vast snake or "Dragon Line" or "ourabouris" which winds complexly between the continents, it takes some sophisticated definitions of coordinates to define it.  The definitions used to establish the statistical models of the rifts are broad enough to include most of the activity in the transverse faults which bisect the Rifts.  The guide for making the definitions was provided by following the world tectonic composite quake maps for the past 25 years or so published by the USGS, maps very much like at the head of this web page.  Most of the expansion rifts are well outlined on these charts and the ambiguous areas are easy enough to just encapsulate into our zones. 

SIDEBAR NOTE ON THE UNDERLYING MODEL USED TO GENERATE THE EARTHQUAKE GALLERY:   This data was individually modeled in various zone spreadsheets and then the summary data was all fed into world_quake_summary.xls.  This spreadsheet provides the base of calculations for nearly all the graphs in the Earthquakes Gallery.  (Because of the enormous size of the quake catalogs, many zones easily exceed the row limitations of Excel within as little as 10 years, making a lot of splicing necessary.  To avoid extremely long auto-updating waits, the charts are all manually calculated and the world sums must be updated by manual copy and paste between files.  Accordingly, this model currently cannot be offered online nor can the charts be refreshed easily.)

All the quakes in the Great Rift are defined as expansion quakes in this Gallery.  In some cases this is an over-simplification, some of the activity is doubtless transverse slippage or transverse block dip strike.  But for our purposes, does it matter?  No matter the exact technical type, they all reveal movement related to expansion and growth of the ocean floors.

On each side of the spreading Rifts we find the continental landmasses where the opposite effect is occurring.  As the Rift spreads, it must push the ocean bottom against the continents, which must in turn thrust against the ocean bottom on the opposite side of the continents.

One of the central dynamics in this appears to emanate with the North Atlantic Great Rift, a spreading rift which splits the Artic ocean, runs down between Greenland and Norway, through the North Atlantic, across the Equator and down to the the tips of Africa and South America where it connects to a circular Rift around Antarctica.  The ocean bottom on the left of the Atlantic appears contiguous with North America.  The ocean bottom on the right of the Atlantic appears contiguous with Eurasia.  Thus both of the entire continents on either side shift as the Atlantic Rift spreads.  Eurasia is pushed against Africa to the South of it, against India (Bharati) and the Indian Ocean Bharatian Ocean also to the south of it, and against the Pacific to the East of it.  North America is pushed against the Pacific.

One interesting discovery in the Gallery is that the databases and graphs make very clear that the Western Hemisphere is not moving nearly as much over the Pacific ocean bottom plates as Eurasia does. 

At all these continental junctures with the Pacific Ocean Plate, the crust comes under intense compression pressures which force intense changes in the nature of the crust.  Complex folding takes place, large numbers of faults can be found, the ocean plate  along the equator is fragmented into many pieces, and most of the world's earthquakes take place around the Pacific Plate (or at least those now currently recorded).  Along with the compression quakes around the Pacific Rim, the continents are visibly altered by major upliftment of mountains and major slumps, such as the uplift of the Great Plains into the Rocky Moutain plateau and the slump of the western U.S.  into the Pacific Ocean from the jagged ends of the Tetons and Wasatch Mountain Spurs of the Rocky Mountain complex.

All the active compression joints where ocean bottom plates are subducting under another plate are instantly recognizable by the huge chains of volcanoes which mark where the tectonic plates are merging into each other.  The pressures inject huge quantities of water and gas from the oceans under the continents, which is eventually turned into intense gas pressure which breaks through the fault zones deeply enough to mix with magma, liquefy it, and provide it with both the exit cracks and the expansionary lift to produce volcanoes.

The volcanoes form along the rim of the water and further inland the collision of the tectonic plates forces a subduction of one edge under another and the upliftment of the edge on the other plate.  That is why you generally find a succession of upthrusted coastal mountain ranges, which are really just long slivers of crust raised up like welts, as well as the long chain of volcanoes, which are simply the vents for the oceanic gasses which the hot magma of the earth has heated to prodigious levels of pressure sufficient to crack and/or push though miles and miles and miles of crustal materials.

Enormous numbers of earthquakes signal all of this  activity the length and breadth of these tectonic collision zones.  This collision activity "sounds" in general to be substantially "louder" than the expansion activity.  By far, most of the seismic activity at Class 4+ is in these contracting subduction zones.  The expansion rifts are more silent with most of their activity well under Class 4. 

The map above which displays the Class 7+ quakes reveals clearly that large quakes in the oceanic Great Rift are extremely rare.  Thus we can readily observe that expansion activity is in smaller magnitudes than compression activity.  This may be consistently true everywhere but we cannot exactly take it as a given at this time. Too much of the Great Rift is not documented for seismic activity below Class 4.  We need everything recorded to really understand the ratios and know their truths.

It may be that most of the expansion activity in the Great Rift is in the magnitude range of 1 to 3, very little of which is being recorded at the present time.  This is a hugely important major scientific problem which needs to be resolved as quickly as possible.  Global Warming "scare money" should be applied to a program of intensive seismic and temperature monitoring of the entire oceanic Rift system.   This is of far greater importance than missions to Mars or futile efforts to abate CO2 production.

Defining The Activity Zones

With the general distinctions well in mind,  we are able to explore the regional zones in which quake activity is taking place.

The maps at the top of this web page displays the distribution of major quakes around the world for periods ranging from 16 to 31 years.  The quakes all appear arrayed in a web of lines which circumnavigate the globe.  These lines in most cases define very well the margins of the Tectonic Plates.

We can focus on the boundaries of the Tectonic Plates which geologists have defined on maps and select specific areas.  As a possible aide, Google has an interactive map of the Tectonic Plates.  But frankly its execution and display is awkwardly slow. Google needs more time to get it right.  So for the time being let us stick with relatively recent efforts by the USGS.

The first map below displays the major boundaries fairly well for the "14 Tectonic Plate Model".  It offers the added advantage of informing us about how closely connected world volcanism is with the edges of the tectonic plates and thus also with earthquake activity.  The second map paints the plates in separate colors to make them easier to perceive as specific zones.

USGS Map of Active Volcanoes, Tectonic Plate Edges, & "Ring of Fire"
This map is clickable to expand into a larger size

Image Source: USGS -  http://vulcan.wr.usgs.gov/Imgs/Gif/PlateTectonics/Maps/map_plate_tectonics_world.gif

 

Map of Fourteen Tectonic Plates
This map is clickable to expand into a larger size

Image Source: http://geology.com/plate-tectonics.jpg
or see Wikipedia, public art in "Tectonic Plates"

The third map, immediately below, will take you into a giant wall-sized map over which you can fly to observe the various tectonics margins which have been painted on to show us how they snake around the Earth.  It summarizes the work of Peter Bird, who has outlined the edges of 52 Tectonic Plates based on current discussions and presentations in the scientific literature circa 2003.  These boundaries are used in Google Earth circa 2007.

Map By Bird Showing The Edges Of 52 Tectonic Plates
This map is clickable to expand into a larger size

The larger chart is high definition and over 10 megabytes in size.

File Link: http://element.ess.ucla.edu/publications/2003_PB2002/PB2002_wall_map.gif

Image Source:  Bird, P.: "An Updated Digital Model Of Plate Boundaries";
(2003) Geochemistry Geophysics Geosystems, 4(3), 1027, doi:10.1029/2001GC000252.
for links to these charts and a PDF of all his material, see also
 http://element.ess.ucla.edu/publications/2003_PB2002/2003_PB2002.htm

Perhaps a bit more practical is this fourth map, also by Peter Bird.  It presents the same 52 Tectonic Plates as does the giant map of plate edges and each plate is colored, as in the USGS Tectonic Plate Map.

Map By Bird Showing The Areas Of 52 Tectonic Plates
This map is clickable to expand into a larger size

Image Source:  Bird, P.: "An Updated Digital Model Of Plate Boundaries";
(2003) Geochemistry Geophysics Geosystems, 4(3), 1027, doi:10.1029/2001GC000252.
for links to these charts and a PDF of all his material, see also
 http://element.ess.ucla.edu/publications/2003_PB2002/2003_PB2002.htm

As can be readily seen in these four maps, there is considerable "tentativeness" about how to model the Earth...really.   The range of 14 to 52 tectonic plates is pretty extreme and Bird suggests that even more plate fragments will be identified on the basis of various morphological and behavioral analysis of actual geological structures.

In general, views and theories of plate tectonics vary widely and this IS NOT a field where the researchers are unified about the basic facts except for this one:  this is a "baby field" and it will take a long time to mature into a consistent story which is widely accepted.

The problem of tectonic modeling gets even worse when you attempt to deal with the directions of tectonic plate motion.  Every chart on the Iway and in the scientific literature seems to diverge in some details from the others, most especially with the details which the author is most focused on presenting.

Bird's direction arrows are all relative to Africa, which is most likely done to provide a sense of absolute motion relative to a large fixed location.  The masses may all have a net motion in the directions Bird indicates, but they are also moving in other directions against each other.  In other words, the plates are moving in two vectors at least simultaneously.  They may as well have three or even four vectors of motion.   By focusing on only the  absolute motion relative to Africa, one loses the net relative motion between many if not all the  plates.   Thus we also lose a sense of the direction and magnitude of the pressure vectors which may be present on the various edges and junctions.  So for the Gallery's purposes, Bird's arrows do  do not help much and some of them may be flatly misleading.  This is especially true with Eurasia, North America, the Carib Plate, and Antarctica. 

I suspect at the current time that any exact model of how the plates move is going to end up being a matter of whose research you chose to ignore. 

A superior model would be based on plate motions relative to the Great Rift which bisects the Arctic and/or the Atlantic Ocean.  Since the average angle of this portion of the Great Rift is close to a 90 angle with the equator, one has a fairly clean, highly defined point of universal reference which is built upon a primary generator of motion in the crust.  By triangulating points on Iceland, Falkland Island, the Great Pyramid at Giza, a peak in Switzerland, Soufriere Hills on Montserrat, something on the Southern tip of Africa, something such as a point near Boston Harbor, and, say, Mt. Baldy in Southern California, one could learn an enormous amount about the real tectonic dynamic at work and the real relative motion of the plates, at least for about 35% of the surface.  Something in the range of 300 points should define the entire planet, including the small "mystery areas" quite well.

Looking at the Earth purely behaviorally, we could avoid much of such work and many of the issues of measuring and recording.  By behaviorally, I mean by looking at the earthquakes and the volcanoes.  Their frequencies and magnitudes will tell us were the Earth's crust is moving the most rapidly and from this we can infer the vectors of relative motion, i.e. which plates are moving the most rapidly in what directions vis a vis their neighbors.  Absolute motion we could just ignore.

If this "anchoring" or "grounding" within the patterns of current quake activity is used consistently to infer primary tectonic motions, I predict that the data from other approaches for defining tectonic motion will fall into greater harmony and consistency.

What makes this most especially realistic is that for the most part we are not concerned with the Tectonic Plates as objects.  Not really. Our interest is mainly about their edges.  These are defined in this Gallery as Tectonic Activity Zones.

The grinding or spreading edges create the earthquakes, volcanoes, ocean climate oscillations, even Global Warming. What we need to do is focus on these edges and define them into distinct "zones" of activity which we can study, analyze, correlate with each other and then parallel with other data. 

As will be seen in the Gallery, this approach can give us  some real perspective.  But we will also see that the Earth is not nearly well enough wired and monitored to give us a full foundation for building the house of tectonics.  Too much essential data for many areas is simply missing.  So the best we can obtain at this time are some crude estimates.  They may not all be entirely correct, but you have to start somewhere.   This is where we start.

Digital Elevation Map From NOAA

Click here to Download 3 MB Digital Elevation Map From NOAA.  Use only  the darkest green color, such as on Florida or California Central Valley, to see what are the tectonic and Global Warming danger zones.  Unfortunately too much elevation is show in green tones. I am looking for a better, finer degree of gradation in elevation, one which clear demarcation at 50 meters, 100 meters, and 300 meters.   This will have too do at the moment.  It is a beautiful imaging job, very nice work, but I have my doubts about how useful it is with so much topography shown in hard to distinguish green tones.  Recommendations gratefully accepted.

This chart below is better for the U.S.

ftp://ftp.ngdc.noaa.gov/GLOBE_DEM/pictures/48USAcolshade.jpg

Other areas can also download these elevation maps.
 Click on NOAA Coastal Relief Maps

Remember, consider only the very darkest green color as your primary risk zone.  We should look for maps which show a much more finely graded steps up in elevation from Sea Level.  50, 100, and 300 meters are to be prized.  Please notify us if you find such maps.

 

Modeling The Tectonic Activity Zones

The Earth is far too complex and old to categorize simply and easily.  Those who do so probably end up in illusions if not delusions.   In fact the Earth is so old that it has changed radically several times. Thus any inference about the changing Earth runs a difficult gamut of evidence which never completely fits into any scheme.  In other words, Plate Tectonics trends of today are most likely are not those of 500 million years ago, nor even of 20 million years ago. 

The evidence of radical shifts appears in every age, strata discontinuity, and continent, even throughout the last two million years.  Climate research through the ice on Antarctica and Greenland demonstrates that the Earth was radically different in many respects some 2 million years ago and has undergone 400,000 and 100,000 year cycles of deep climate shifts since then.

It does not appear that human science has a handle on this other than  large repositories of local research data which shows many trends and changes and shifts which are occasionally contradictory with other areas.  If you add in bizarro phenomenon,  such as entire blocks of crust which have turned in circles at the East Pacific triple junction, or such as blocks which have turned bellyside up in the interior of continents, you have a potpourri of diverse stories which are not easy to summarize into the same geological theories.  The more one looks, the more it seems that Earth history is stranger than we can imagine.

Trying to model the motions of the Earth gets even more strange.  When we attempt to define the expansion and contraction zones of current Earth dynamics, we run immediately into the problem that some large sections of tectonic plates show evidence of moving in contradictory directions at the same time.  North America as a whole, for instance is moving to the West and South by some measurements, or more to the West and North by other measurements, yet the coastal zone of the Pacific Northwest is showing movement to the Northeast.  That's just for starters.  Any one for tea?

Then there is the strange case of the thin but quite long Baja Crumple (which slides along the coast of California and Northern Mexico.  Once called a tectonic plate it appears to have been downgraded to just the eastern edge of the Pacific Plate because no one can find a western edge for Baja except on the other side of the Pacific Ocean.  It is pushed from the south by the Cocos Plate which is subducted under Northern Mexico and perhaps along the Southern California Coast.  It is even yet still possible that the concept of a collision by an independent plate will be resurrected in the form of the the Cocos Plate under the Pacific Southwest.

For the time being,  it is convenient to think of the Baja Crumple as a unique segment of crust, a quivering sliver of ocean sediments turned into high piles of mountainous crust which is the product of both the Pacific and North American Plates grinding as they slide past each other, with the Cocos Plate and Rivera Platelet thrown against them from the south to keep everything confused.   This Crumple grinds against North America, producing Southern California’s high mountains as it goes.  As it passed, it produced the Santa Monicas with an offshoot through the Hollywood Hills,  the San Gabriels, the San Bernardinos, and of course several other major  mountainous crumples which form Southern California from Santa Barbara to Nevada and from San Diego to the Colorado River. 

Bird's Google Maps will tell you that the San Andreas Fault is connected to the East Pacific Rise, but sources in Mexico will tell you that the East Pacific Rise subducts under North America in lower Mexico.  Care for another cup of tea?

Then there is the matter of slowly moving crustal deformations (silent earthquakes), gradual subsidence or swelling which is measurable from year to year, and lunar (monthly) land tides which rise and lower the land each month by centimeters or millimeters.  All these motions are not easy to resolve in any general model of Earth's shape-shifting yet they all play a part in shaping the crust.   Since all the measurements of annual motion are in the range of a few millimeters to several centimeters, we are in any case dealing with measurements which are very hard to contrive with something the size of the Earth, which, above all, is moving ceaselessly.  Ever try to measure the height of a wave from your rowboat?  It is very hard to find a stable point of reference by which to even make a crude guess.  Subjectivity, error, mistaken presumptions, all can easily cloud our vision of such details.

Accordingly, exactly in what directions the crust, or better said, various portions of the crust, are moving, really, IN THE LONG TERM, or, AT THE CURRENT TIME, is a seriously open question.  It is probably practically impossible to answer such questions decisively  if the measurements come from short term data bases of less than 50 years.  Most of what we consider long term is just a brief flutter in geologic tectonic time.  A longer range cycle (more than 50 years) could begin to switch directions tomorrow.

And of course all humans have are databases which are generally less than 50 years deep, and incomplete for many areas.  They contain just enough "flutters" to give you a glimpse of some light and fuzzy outlines, but the devil is in the details which ellude us now and probably will for many centuries or more.   In other words, infant humanity and its play-pen science cannot yet obtain reasonable objectivity on long term issues and trends. 

The best we can do from the base of our existing empirical science is to speculate some basic concepts, such as "Plate Tectonics", and seek empirical means to refine them.  Therefore the Earth Changes Gallery begins with an empirical base of measurable earthquake activity which is organized into zones by some general concepts and data about plates tectonics such as seem to have been widely accepted. Most fortunately, despite the sadly incomplete and sometimes shallow data with which we must make do,  we are still able to make some reasonably clear observations.  From these we can make some reasonably real projections and speculations about the trends in geological and geophysical activity which are producing the changes in the Earth.  Already, this approach provides findings which are superior to the modeling on which the CO2 theory of Greenhouse Gas is built. 

The Use of Google

Where can we start, short of perfect objectivity?

Well, one thing we can do is use Google Earth.  Despite the criticisms above, Peter Bird has outlined more of less the latest quality definitions for various tectonic plate margins and built them into the "Google Earth" model.  (Simply google the name to acquire the latest best links which introduce it).

This tectonic plate structure on Google provides an excellent foil with which we can use some common sense deductions to generate our “zone” definitions for the primary tectonic quake zones.  Based on the lines drawn on the map, using the displayed quake activity as an underlay or overlay,  we can define a gridwork of Longitude and Lattitude numbers to encompass various active zones.  These definitions we can then feed into planet-scope earthquake catalog servers (such as ANSS Composite Catalog) to create a selected “database” for each of our zones.

This works quite well, as the Earthquake Storyboard demonstrates, but the data load is far in excess what Excel can process.  With existing servers and software, this works after a fashion but not as elegantly as one would prefer.  One has to go slowly and select partial data slices to get anything done. It definitely is not easy because of the collision of demands of KISS, the demands of the catalog servers, the inadequacies of the PC, and the nascent awkwardness of Google Earth (which is very young).  

Unfortunately  Google Earth is not nicely compatible with attempts to multi-process on a PC.  It is too imperious in resource use for the average PC of the first decade of Century 21.  That said, Google is a terrifically useful tool for visualization of data if you have the patience and computing ability to cope with it.

The Use Of NOAA World Surface Model

Poster - Surface of the Earth, March 2000 Revision

A FABULOUS DIGITAL MAP SYSTEM FOR EARTH.  High quality images of the zones, far superior to Google images, can be found by using the digital World Surface Model produced by NOAA.   GO HERE TO CLICK ON SECTIONS TO ZOOM IN ON IT.  One can quite easily define precision boundaries of the tectonic zones using this model as the final guide.

NOAA ETOPO2v2 Global Gridded 2-minute Database

Two-minute gridded global relief for both ocean and land areas are available in the ETOPO2v2 (2006) database.
http://www.ngdc.noaa.gov/mgg/image/2minrelief.html

Formal Citation:  U.S. Department of Commerce, National Oceanic and Atmospheric Administration, National Geophysical Data Center: "2-minute Gridded Global Relief Data (ETOPO2v2)", 2006; http://www.ngdc.noaa.gov/mgg/fliers/06mgg01.html
 

The Use of Polygon Parameters and Map Coordinates

 The zones all use coordinates of Longitudes and Latitudes, often comprised of multiple sets to define “polygon” structures or  zones of many sides to encompass large unsymmetrical areas of the Earth.  Almost none of the activity zones come in convenient rectangles or circles which can just defined as four points on a map or as one point plus a distance radius.    To create our activity zones we have to use what have become called "polygon parameters".  In a few cases we will have to add two blocks together.

The ANSS Composite Catalog defines the task this way:

You may specify a polygonal search area with the polygon parameter. This takes the strict grammatical software structure of:

polygon=lat_1,lon_1,lat_2,lon_2,,...,lat_N,lon_N

where lat_i,lon_i specify the latitude and longitude of the i-th vertex of the polygon. In other words, you can define as many pairs as you  want in order in the same consistent direction to outline any complex shape you want. The last point is identical to the first point in order to "close" the polygon. Blanks are not allowed.

For example

  polygon=37.4,-122.7,37.9,-122.75,37.9,-122.3,37.0,-122.0,37.4,-122.7

    This defines a polygon which encloses that Bay Area Peninsula.

All south latitudes are negative numbers, all north latitudes are positive numbers.  You do not use N or S to specify which side of the Equator you are on.

All longitudes east of Greenwich Meridian, are positive, all to the west are negative.

The polygon you describe must NOT cross the -180/180 degree longitude boundary, THE INTERNATIONAL DATELINE because the algebra will meltdown.  This little gem is a huge headache and needs to be solved by using a grown-up and mature non-anglo-centric 360 degree coordinate system for the Longitudes.  Why scientists in Century 21 are still pissing around with this antique West and East system invented for use by euro pirates is beyond me.

Conventions of Numbers, Lats, & Longs

For describing the zones, since I cannot focus on numbers nor abstract directions as proper cognitive objects by which to process information, the following convention is used to describe points on the Earth as intersections of our reference lines.  Longitude or Latitude is always specified first.  This gives me the imaginary Proper Noun object to process.  Then comes the qualifier which tells me which direction into which half the Earth to look,  West or South   or North or South.  Then come the numbers which specify exactly where the intersections come together.  It is very simple, very clear.  One never makes a mistake with it.  It is nearly the opposite of the scheme used by academics.

 Model Specifications

For All World Quakes, use these scales where ever possible:

Zones & Margins:  Be practical, for the most part use 14 Plate Model

Draw Zones Widely:  draw in as much associated activity as possible

All Earth =>6

All Earth =>4 & <6

All Earth =>2.5 & <4  (desirable but not practical with PC)

Unless highly qualified, do not use data prior to 1973.  Do not use data younger than 60 days.

Exception Number One:  Southern California, use from 1932, 3+

 


Definitions For The Expansion Rifts

We will begin with the Expansion Rifts, which are composed of essentially four great parts:  the west to east running Antarctic Rifts around the southern end of the Earth, the north to south running Arctic-Atlantic Rifts, the south to north running East Pacific Rifts, and the south to north Indian (Bharatian) Rifts.  Many names have been given to various parts of the Great Rifts but for the most part this Gallery ignores them to concentrate on the largest scale units of Earth's dynamics.  We are striving to find the simplest level, not the most complex.

The Expansion Rifts, or course, are where the crust of the Earth is separating apart.  This allows new crust to slowly form from out of the Earth's deep liquid magma beneath the crystallized shell of the outer surface (which is typically called the lithosphere).  Curiously, the Expansion Rifts do not produce very many major quakes, their activity is generally in the lower magnitudes (under Class 4). 

xxx edit below this definitional portion of the storyboard is fairly raw.  formats, links, and grammatical structure need major editing

Antarctic Rifts - Definitions

It runs west to east around the southern end of the Earth. As can be seen in the charts above, the Antarctic Rifts comprise by far the longest rifts.  The Antarctic Tectonic Plate is huge, much larger in aggregate than the very large continent of Antarctica which composes the middle of the Plate. The Antarctic Plate is in essence the entire bottom of the Earth 360 degrees in round through all the Longitudes, mostly everything south of Latitude South 50.  That is an enormous chunk of the Earth.

 The margins of the vast plate are not easy to define, have not been completely defined, and almost certainly are not understood by a single human well enough to define with precision.  Part of the problem is its remoteness.  Almost all of the margin lies deep under oceans far to the south over which almost no one sails nor flies.  Thus is it not much observed and there is about zero incentive to want to observe it.

It is said to be mainly a spreading rift zone with some areas looking like transform (horizontal) slip faults (as under the tip of South America associated with the Scotia Plate and the Falkland Islands). It also is said by some to be moving in a circle, mostly moving, relative to all the other plates, in the same direction as the Earth Spins.  If this is so, then the spreading rift which encircles Antarctica must be largely produced as a result of the Indian Ocean Bottom and the Pacific Ocean Bottom Plates moving to the north while Antarctica remains virtually static in its north-south movement. 

At the bottom of South America, the Atlantic Ocean, and Africa, the margin mainly appears to behave more like a vast transform slip fault zone than a spreading rift. There is relatively little north-south motion between them.  Antarctica can be said to be scraping past them, or perhaps South America is scraping past the edge of Antarctica.  According to recent high technology measurements made by the JPL, there is not much net movement in Antarctica.  JPL indicates a small net easterly migration, much slower than the active areas to the north of it. 

To avoid stultification by the complexity, we begin by simply making the assumption that the margin of this plate  is all an expansion rift at the bottom of the Earth.  We ignore the issue of how much of  some portion of it may be more like a transform slip zone. 

So we dive in and use the Google plate margin boundaries around Antarctica to define the entire zone as an expansion rift.  Since there are few recorded quakes above 2.0 for the entire interior portion of the Antarctic Plate, we can simply block the entire continent into this zone.  (Quakes up to 3.99 may occur there in the interior but they simply are not being recorded and logged circa 2007).

For various reasons we have to get complex in a polygon structure to encompass the zigs and zags which shoot alternatively to the  north and south in the Indian Ocean and the Pacific.

Because of international dateline and software limitations, we cannot specify a zone which passes through the dateline.  Thus we are forced to model these quakes into at least two polygon files

Partly to keep the polygons manageable and partly to observe the possible existence of different behaviors,  this vast rift is best divided into at least three major sections:

Antarctica-Bharati  Definition

Lat South 52, Long East 180

Lat South 52, Long East 145

Lat South 45, Long East 145

Lat South 45, Long East 100

Lat South 24, Long East 100

Lat South 24, Long East 50

Lat South 35, Long East 50

Lat South 40, Long East 40

Lat South 40, Long East 0

Lat South 90, Long East 0

Lat South 90, Long East 180

Lat South 52, Long East 180

polygon=-50,0,-60,0,-60,180,-50,180,-50,145,-45,145,-45,100,-25,100,-40,40,-25,40,-40,10,-50,10,-50,0

The first portion along the date line is a little problematic near the Triple Junction of the East Indian Rise. 

The final portion is even more problematic.  It truncates at Long 0 and thus ignores a section of the margin between the Falklands Fragment and the Triple Junction which is formed with the Atlantic Rise nearly dead on the Prime Meridian.  Rather than song and dance this into the Ant. Margin, this zone is simply added to the expansion zone of the South Atlantic.  It is, after all, in the middle of the South Atlantic and most of the interpreted activity is characterized as transform slippage due to the expansions of the central Great Rift in the South Atlantic. 

Antartica-Pacific  Definition

Lat South 30, Long West 77

Lat South 30, Long West 130

Lat South 50, Long West 180

Lat South 90, Long West 180

Lat South 30, Long West 77

polygon=-30,-77,-30,-130,-50.-180,-90,-180,-30,-77

Atlantic Zone of Ambiguity

From the East Pacific Triple Junction (near the Easter Islands), the Antarctic Margin past the tip of South America and into to the bottom of the Atlantic Ocean, to the Scotia Triple Junction, at approximately Long. West 2,  shows very complex mechanisms involving subduction, transform slippage, crustal deformation, and crustal rifting.  Here what we see as the tip of South America is more or less slipping to the West (relatively speaking) past the edge of the Antarctic Plate.

To accommodate the complex collisions in this area of the Pacific, South American, and Antarctic Plates, exclude Long West 77 to Long West 50 from the Antarctic Margin and incorporate into the South American Compression Zone.

It is not likely that there is significant subduction between the two plates of South America and Antarctica, though the volcanoes on the Scotia Plate are likely the tattletales of such a zone.  Evens so, we will categorize all the remaining activity in the Atlantic as part of the Antarctic Rifts.

The leg of the margin which runs from the  lower Triple Junction of the East Pacific Rise is probably NOT a boundary of Antarctica.  This section of ocean bottom is probably best described as a separate fragment, like the Nasca and Cocos Plate Frags to the north of it.  But since this is reputably a classic expansion rift, and since the edge of Australian plate below is virtually tectonically silent, thus locked with little or no actual relative motion in class 4+, we can treat this as the de facto statistical edge of of the Antarctic Plate.

Arctic-Atlantic Rifts -  Definitions

This famous artist's drawing of the ocean bottom displays most of this vast rift very well.  Here is about the best image yet of  Loki's Dragon breaking the bounds of Hel.


Heezen Artist's Map
NOAA - USGS

The Atlantic Rift begins at the triple junction on the transform slip margin of Antarctica near the Falkland Islands and extends all the way up past Greenland though the Arctic and straight into the Siberian Eurasian mainland, which is “flowing” over it in some way not yet generally understood.  Or perhaps it just peters out there near the continent.  The situation is not exactly clear but seismic patterns suggest that it dives deeply under the Siberian mainland.

This great cleft in the Earth is producing a major portion of the pressure gradients in the crust.   Like a vast "hinge", it slowly opens, forcing the eastern and western sides to either side.

For analytic purposes, as well as for convenience in defining polygons, this Great Rift is best defined in three segments:

Arctic Definition

Click On This For Gorgeous Expanded Version

NOAA NEW IBCAO RP-2, 2004 Poster

 

For our purposes, this portion of the Great Rift begins at the shores of Siberia in the Artic, runs past the North Spin Axis, down to the east of Greenland, and over Iceland (which is actually a part of the spreading Earth) .  In the north we begin at Lat North 77 (+22m) at Long. East 126 (+58m).  We define a zone which encompasses a major portion of the Arctic and head south. 

The coordinates for this zone are a simple circle to Latitude 75.  The search parameter is written as such:

search criterion: delta=0 km to 1600 km from (90,0)

This is the entire Arctic centered on the geographic north pole and  extending out to Latitude 75 all the way around.  This overlaps both Siberia and the Canadian Arctic islands slightly but not much and avoids the complexities of eastern Siberia and Alaska zone, which are handled separately. It is nearly certain that virtually all recorded quakes in this zone are directly connected to lateral expansion pressure forcing the growing of the crust through the Atlantic.

North Atlantic Definition

This portion runs down through the middle of the North Atlantic past a "triple junction" (which is west of Spain) down to near the Equator where it passes another triple junction with a vast transform fault connected to the Carib Plate.  At the Equator we pass to the next segment.

The coordinates for this zone cut cleanly close to the central Great Rift to avoid most of the compression slip zone between Africa and Europe

The polygon overlaps Greenland a small amount, but this is statistically insignificant.

A great deal of "staircasing" is required in our polygon to bypass Europe.

polygon=75,-50,75,10,65,10,65,-10,40,-10,40,-24,10,-24,10,-56,40,56,40,-40,65,-40,65,-50,75,-50

South Atlantic Definition

polygon=10,-54,0,-55,0,-34,-50,-34,-50,-20,-65,-20,-65,0,10,0,10,-54

 

 

 

East Pacific Rift Definition

The East Pacific Rift is a spreading rift not unlike the Atlantic Rift.  Like the Atlantic Rift, it runs south to north, thus paralleling in on the other side of the Americas.

It begins from a triple junction with the Antarctic Rift and runs over the Equator tending strongly to the North.  It eventually intersects with Southern Mexico, or runs along the coast of North America, take your pick of the literature and maps.

There is nothing straightforward about this Rift.  This zone poses some problems of  interpretation of many complexities. 

The transverse nature of the Western Hemisphere relative to the East Pacific Rise and continents requires a complex stair-stepping polygon structure to exclude the compression zones and include as much of the expansion zones as possible.

NW Point:  Long. West 107 at Lat. North 19

NE Point:  Long West 81 at Lat North 4

SE Point:  Long West 136 at Lat South 45

SW POint:  Long West 132 at Lat South 23

West Edge: Long. West 120

North Edge:  Lat North 17

then east to Long. West 104

then south to Lat North 16, Long West 104

then east to Lat. North 16, Long West 102

then south to Lat North 10, Long West 102

then east to Lat North 10, Long West 88

then south to Lat North 4, Long West 88

the east to Lat North 4, Long West 83

the south to Lat South 32, Long West 83

then west to Lat South 32, Long West 120

then north to Lat North 17, Long West 120

polygon=17,-120,17,-104,16,-104,16,-102,10,-102,10,-88,4,-88,4,-83,-32,-83,-32,-120,17,-120

The Southern Half of the East Pacific Rise is very active, spreading at 61 mm/yr, with the observed northern portion (Gorda plate rift) spreading at 39 mm/yr. (Google Earth).   One would expect the rate of rifting to slow down the further from the Equator one gets…and these facts, at least in the Northern Hemisphere, seem to bear this out.

Does the slow speed of North America act to "hold" and “pull” the East Pacific fracture apart along its eastern side, while the Pacific bottom plate migrates the western side to the northeast?

The Bird Model shows the East Pacific Rift running from  Baja to Alaska.  With the exception of the Santa Ana portion of Southern California, the rift runs  fairly far out to sea parallel to the Oregon/BC Coasts to Alaska and into the Arctic

Up to its point of intersection with North America in southern Mexico, the East Pacific is clearly an expansion rift. 

From Mexico all along the coast to Alaska, the rift acts as a transform slip which slides the Pacific to the Northeast at a faster rate than North America is pushing from the East to over-ride and  subduct it.  The result is that North America "crumples" along and over onto the edge of the slip zone.  The crumples are  compressed into a string of coastal mountains which move progressively to the north along the coast of North America.  For this reason we can catagorize the East Pacific Rift as terminating off the coast of Mexico and everything to the North of this junction is merely a subduction or transverse compression zone

 
Indian (Bharatian) Rift Definition
 

 

 

 

The Northern portion is complex.  All in all, the Arabian, Northeast African zone, with the active rifting in the zone from Ethiopia to the Triple Junctions in the middle of the Indian Ocean down to Antarctica are very difficult to reconcile with any one source of data.

For simplicity, the Bharatian Expansion Rift includes all of the rifts around Bharati (India).  The northern edge of the Bharatian Plate (Indian) if of course purely Compression Zone and this edge is defined as part of the Eurasian Compression Zone.

This expansion zone has one major south to north rift with several names which are all part of the Indian Ocean Rise.  This expansion joint rises from a triple junction on the Antarctic Rift.  It passes a triple junction which runs to Southeast Asia and continue on to reach a triple junction near the Gulf of Aden.  From this juncture,  one leg leads into Eritrea (Ethiopia) through the Red Sea and forms another Triple Junction with the great crack which forms the Great Rift which runs through East Africa all the way to South Africa.  Maybe, the models get somewhat tenuous here.  

This rift on Africa  is not currently an actively spreading great rift like the Ocean Rifts.  If appears to be acting more like the downfaulting zone which runs through North America through the Mississippi River into the Great Lakes and thence to the St. Lawrence Seaway system.  The continent is deeply faulted here and may be “hinging” through this fault into a deeper and deeper divide. Some speculate that an East African plate fragment is breaking off Africa but in this age of the Earth, this breakage apparently is “locked” into relative inactivity.  Because of the ambiguity and lack of data reports, most all of Africa from Eritrea  is excluded from all other zones. To the north, all goes into Eurasian Compression Zone, to the South, no assignment is made.

The Red Sea and the Persian Gulf were obviously formed by the same tectonic forces in roughly the same tectonic epoch.  Like the East Africa Rift, they appear also to be expansion rift products.  But currently they may be compression products, huge radical downfolds and slip faulting of the same general nature as the Mediterranean.  For the most part they may be currently in geologic hiatus -"tectonic dead zones".  Regardless, as much as possible of these zones are defined as part of the Eurasian Compression Zone.

Another leg from the triple junction near the Gulf of Aden leads is apparently a “convergent” or plate margin locked against the Arabian Peninsula (most likely an independent Tectonic Plate).  This margin leads up to  to Iran and the Gulf of Aquaba where things are complex indeed, forming essentially very radical compression zones against the Eurasian continent.  The edges from the Persian Gulf Triple Junction run up to Pakistan and the Indus River Zone and thence up to the Himalayas where the plate edges connect to the Great Collision Zone.

The Great Collision Zone is is easy to spot, it is the Himalayan Belt. As much as is practical, this area is defined within the Eurasian Compression Zone.  The greatest activity appears to be in the Red Sea and the Persian Gulf, which appear to be mainly ultra-depression downfaulting compression zones.   Accordingly, all leading up from the Persian Gulf to this zone are part of the compression zone of Eurasia.

Both the Indian Ocean Plate and the African Plate are shoving up against Eurasia, with just enough "twist" to make the Indian Ocean Rift a spreading zone all the way into Eritrea.  How this makes sense with the enormously huge uplift of the Ethiopian Plateau, which is about on par with a major portion of the Rocky Mountains, is not something which I currently comprehend.  Or is that simply the legacy of an earlier age and times have changed?

The bottom point of the Indian Ocean Great Rift is a Triple Junction which connects it to the Antarctica Tectonic Plate.  Theoretically, the Earth is spreading in at least two different directions to the north of Antarctica from this triple junction point in the southern Indian Ocean.  One direction is to the northwest, pushing Africa to the North with a western twist, another direction is to the northeast, which is strongly pushing Australia to the northeast up and over the Pacific Bottom Plate.

Since all of this zone in the middle of the Indian Ocean is expansion zone country, where to draw the boundary is fairly arbitrary.  Latitude South 25 seems like a simple number reasonably accurate enough for this purpose. 

There is another triple junction in the middle of the north-south section of the Rift which is far more problematic.  A transverse/expansion zone is declared running   to Northern Sumatra to connect at another Triple Junction Compression Zone where the edges of the Australian and Eurasian Tectonic Plates meet.  Except for the triple junctions, this zone does not appear to be very active, or at least very little is being recorded for this long west-east transform expansion zone.  The junction with Sumatra is treated as a termination and all the activity at that point is assigned to the Australian Compression Zone.  As news during the past few years makes self-evident, there is enormous stress and activity in the Sumatra Trench at and near to this Triple Junction.

West Edge: Long. East 42

North Edge:  Lat North 15

then down to Lat North 8

then east to Lat North 8, Long East 55

South Edge:  Lat South 25

East Edge:  Long. East 76

polygon=15,42,8,42,8,55,-25,55,-25,76,15,76,15,42


Definitions For The Compression Zones

The Great quakes (7+)and most of the major quakes (4+) are produced in the Compression Zones.  Many unique zones can be defined, but it is most convenient to deal with only eight or nine definitions to encompass the entire earth.

Five broad areas - Eurasia, Africa, Western Hemisphere, Aleutians-Alaska, and the Western Pacific

Eurasian Compression Zones

(map images do not correspond exactly with definitions)

Eurasia

From Iceland, we pass by two triple junctions in the Great Rift before we reach Antarctica.  The northern triple junction connects the Great Rift with a transform slip zone which quickly becomes  a subduction and  slip joint running between Africa and Eurasia.  Thus this triple junction in the North Atlantic is the terminus, essentially, of the vast continental collision zone between Eurasia in the north against  Africa, Arabia, India, and Australia moving up from the South. 

For many reasons, Southeast Asia, Northeast Asia, and Australia are excluded from the Eurasian numbers and are presented as  distinctly different zones.

Points

Western Edge:  Long. West 25

Southern Edge: Latitude North 25

Northern Edge:  Latitude North 55

Eastern Edge:  Long. East 110 plus

North 75

East 100

down to North 20

over to East 40

down to North 15

over to WEST 25

up to North 55

over to West 12

up to North 65

over to East 5

up to North 70

over to East 20

up to North 75

Qualifers:

The Eastern Edge in the Southeast China Interior  overlaps the Western Pacific Rim definition.  Statistically this overlap is probably not significant.

Some compression belt in Mongolia is lost since it falls into the zone for Japan & East Asia.

East Bharati (India)

(map images do not correspond exactly with definitions)

This appears to be a transverse slip compression zone, with many parallel compression belts.

This is a rump zone which was defined separately for convenience and to check out dynamic flux in this complex junction between Eurasia, India, and Australia.  It is an ambiguous area, not sure where it should go:  Philippine Plate?  Eurasia?  May best be consolidated into a Philippine (Southeast Asia) Fragment Plate definition which is wedged between four others, similiar to the Carib Plate and Honshu Island (Japan).

Note that these fragments, wedged between four or more, are primarily located on the Equator, which is what we would expect with the dynamic of vortexian (spin) mass movement supplying the principal source of energy for plate fracturing and creep.

North 5, East 90

up to North 17

over to 100

down to North 5

back to start

Aleutians-Alaska

(map images do not correspond exactly with definitions)

The Pacific and North American plates are said to be moving currently in approximately the same direction- to the northwest, with some zones of North America showing some more purely western and even southwestern movement.

Accordingly we must exclude a broad zone of the Aleutians-Alaska from North America.  A great portion of Alaska is moving VERY  southerly.  This zone runs from the Cook Inlet on the neck of the Alaskan Peninsula to the Kamchatka Penisnula.

This area appears to be moving in approximately the same direction as Eurasia is moving, at a fairly stiff opposition to the Pacific Plate.

If so, we may have a separate plate fragment - call it Alaska-Siberia, a rather large plate wedged between Eurasia and North America.

This platelet appears to be "locked" relative to Siberia, but in collision with both the North Pacific and North America. In the mountains of eastern Alaska, we can see the welding of Alaska-Siberia into North America as the rapidly spreading North Atlantic pushes North America into the Alaskan-Siberian fragment.  This would appear to be very much as the Himalaya region.

Hence the Aleutian-Kodiak Islands and the vast mountainous region of eastern Alaska, Yukon, and Northern BC.  The Aleutians, all volcanic tops, comprise the zone where this platelet is most rapidly advancing over the Pacific Plate.  The Great Neck zone is the area of opposition between North American and the Alaska-Siberian Plate (if we can presume the region to exist as such).  Neither appears in the mood to subduct, accordingly the land masses are folding and stacking up high.

There is a decidedly interesting symmetry of vector motion and actual quake behavior if this is true.  From the North Atlantic, Eurasia is hinging  to the east, with a south twist, while North America is hinging to the west.  Eurasia shoves against North America in the region of Alaska. Their mutual collision forces deformation of both continents towards the south. North America cartwheels very slowly in a counterclockwise spin, slightly overriding the Pacific Plate while remaining essentially locked against both the North Atlantic expansion and the Pacific expansion. 

Naturally, if this were to be the case the greatest amount of tectonic activity in North America would be in the Alaskan collision zone.  As a matter of fact this is exactly the case with both volcanism and earthquakes.  As one looks at the actual behavior charts (earthquakes) one finds that activity in Alaska overshadows the rest of North America combined.

Most of Eurasia, however, from the Kamchatka Peninsula down through to Borneo on the Philippine Plate, is free to rapidly subduct the Pacfic Plate and its fragments, which includes the Philippine Plate, and the shaky platelets on which the people of Japan ride.  And in fact, once again the actual behavior charts reveal this.  Study of the maps suggests as well that Eurasia is subducting the Pacific Plate so rapidly that a double parallel row of subduction zones has developed on the western edge of Eurasia, making its geology complex indeed.

Points:

in the north from Lat N 75

Rect. Sides

North 75

West 140

North 50

West 180

    * minimum latitude=50

    * maximum latitude=75

    * minimum longitude=-180

    * maximum longitude=-140

    * minimum magnitude=4.0

Japan & East Asia

(map images do not correspond exactly with definitions)

Northeast Asia

Japan - This definition goes out to the dateline to catch in the western Aleutians and goes all the way east into Mongola.  From North 75 to North 24 of the eastern edge of Eurasia.

    * minimum latitude=24

    * maximum latitude=75

    * minimum longitude=115

    * maximum longitude=180

    * minimum magnitude=4.0

Western Pacific  (Philippines Plate)

(map images do not correspond exactly with definitions)

This zone is  contrived to keep this entire zone of Eurasian subductions in a basic north-south orientation.  The horizontal subductions are all defined under Australia.  Since this is not an optimal definition for the Philippines Plate because it includes some of Southeast Asia.  Thus I am not calling this zone by that zone.  That said, most of the quake activity in this area is connected with subductions of the Pacific Plate or by subductions of this plate by the Australian Plate.  

The geology here is not well described at this time.  There are many complexities and apparent plate fragments.

    * minimum_latitude=5

    * maximum_latitude=24

    * minimum_longitude=115

    * maximum_longitude=180

Western Pacific

East 180

North 24

East 115

North 5

Australia & New Zealand

(map images do not correspond exactly with definitions)

We have here without a shadow of a question the most active tectonic zone on the planet. About one third of the earthquake activity 4+ occurs on the northern and eastern edges of this Tectonic Plate, which is much larger than the large islands and rump continent which form its interior portions.   Because of the huge number of  quakes below 4.0, no attempt to model them on this PC has been made.

A count of volcanic activity would probably come to the same general conclusion, though no count seems to exist at this writing.

The bottom of the Australian Plate is all expansion rift and activity along this rift is all defined into the zone for Antarctica. 

Australia is moving rapidly (relative to all other plates) to the north and east away from Antarctica. It is colliding strongly with the Philippine Plate (and frags) or perhaps what is now better known as Southeast Asia.

We define all the eastern, western, and northern edges of the Australian Tectonic Plate as compression zones produced by Australia generally trending toward the north to subduct edges of the Eurasian, Pacific and Indian Ocean Plates.

The zone as defined below includes all of Indonesia, a portion of Southeast Asia, New Zealand, a great many of  the tropical South Seas Islands from Papua New Guinea, the Solomons, Tonga, Fiji, New Zealand, and other island groups.

The western edge appears primarily as a transform slip joint with the Indian Ocean.  Both sides are sliding mainly towards the north.  Some expansion activity is probably also present but the model currently ignores this issue. 

The eastern edge is a very complex business to challenge any modeler.  The Google Earth "map lines" instill no confidence of an easy solution.  Essentially New Zealand is a shaky place producing a major portion of Australia's quake activity because it sits on a vast transform slip joint between the fast northerly-moving duo of the Pacific and the Australian Plates.  Even as they slide by each other, the Australian Plate is busily subducting the Pacific Plate and all the islands are essentially the result of the subduction process.

Primary Area:

polygon=5,94,-40,94,-40,135,-45,135,-45,155,-50,155,-50,180,5,180,5,94

North 5

East 94

There is one complexity introduced by the international date line and the inability of the geophysical and quake databases to think within a framework of 360 degrees.  This limitation unfortunately bisects New Zealand, making stats for this highly active zone (about 10% of world activity 4+) a bit awkward. This is handled by the following "add-on" definition, which includes most of the South Pacific Island groups to the north and east of New Zealand.

South 50

North 10

West 180

West 165

Western Hemisphere Compression Zones

(map images do not correspond exactly with definitions)

North America

Western North America
(AKA Northeastern Arc of the Pacific Rim of Fire)

 

 

 

Western North America Compression Zone: from Alaska Great Neck to Southern Tip Baja; excludes Alaskan Peninsula & Cook Inlet

Plus Northern Pulled Rift Zone (continental subduction of rifted ocean plate): Gorda, Juan de Fuca, Farralon

Plus Southern Pulled Rift Zone (continental subduction of rifted ocean plate):  Baja Transverse Slip Rifts

filename: WESTNA

North Edge: Lat North 75

West Edge Long. West 140

South Edge:  Lat North 20

East Edge:  Long. West 105

 

Uses “Decimal Degrees” for rectangular area as follows:

Top = 70

Bottom = 23

Right = -105

Left = -140

South Edge is problematic; the problem is the East Pacific Rise which strikes Mexico nearly at this point

The southern edge was set at Lat. 23.  It was specified to force Colima, central Mexico, all of Yucatan, almost all of Cuba, and of course all the Carib islands to the South into the Carib Zone.

The right edge was set at Long. 105 to place the New Madrid and St. Lawrence fault zones, and the entire interior continental schlump down the Mississippi River Valley into the zone for Eastern North America.

Eastern North America

filename: EASTNA

Defined to include as much of the Missouri/Missippii Continental Depression zone as possible, thus this area measure the New Madrid Continental Fracture and it also covers the St Lawrence Seaway and Greenland continental fractures.  (Greenland is technically a portion of the North American Tectonic Plate which is gradually breaking free of it through the passage up its western edge to the Arctic.)

Greenland is problematic.  This definition ignores Greenland and bisects it strangely in the southeastern portion.  Greenland is not known to be tectonically active, thus the statistical implications of this definition are probably not significant.

North Edge: Lat North 70

West Edge Long. West 105

South Edge:  Lat North 23

East Edge:  Long. West 50

    * minimum latitude=23

    * maximum latitude=70

    * minimum longitude=-105

    * maximum longitude=-50

Southern California

This area is under intensive study and detection development programs operated cooperatively by California educational institutions, the USGS, and other public institutions.

The zone is rigorously defined as a rectangle between Latitudes North 32 and 37 and between Longitudes West 122  and 114.  Earthquakes produced here are compression subduction or transverse slip, depending upon the fault complex (there are many interconnected fault zones throughout this area).  Most of the major activity is apparently transverse slip related to some segment of the Santa Ana Fault, which is a local name given to the East Pacific Transverse Slip running from Central Mexico to Alaska.  Technically the East Pacific is an expansion rift but North America is compressing and subducting both sides of this rift throughout most of its distance along the western edge of North America, most especially from Baja California to the Queen Charlotte Islands in British Columbia.  Little expansion is occurring on this rift, thus the entire zone is best described as a compression zone.  An exception could be made for the Farollon, Gorda, and San Juan Plate Fragments in the Pacific Northwest (Oregon, Washington, British Columbia) along which some genuine expansion rift activity is now well documented, but it probably is not worth the effort for a planetary level perspective.

Aleutians-Alaska
(categorized and summarized within Eurasia)

xxx edit add link

Carib-Cocos Tectonic Zone  

(map images do not correspond exactly with definitions)

 The Carib Plate is a fragment of North America or South America which is moving more rapidly than either of these two large continents. 

Doubtless the Carib Plate is actively subducting both the Atlantic and the Pacific Plates (the Cocos Fragment)  simultaneously.   How it manages do so with the vectors of motion which are described by various sources is a Great Mystery.  It may be that the Carib moves relatively little, it may be that all the other plates are moving around it while both the Pacific and Atlantic are moving to tunnel under it (both being subducted).

* polygon=6,-102,17,-102,17,-104,23,-104,23,-56,6,-56,6,-102 ,6,-102

West Edge: Long. West 102 up to Lat. North 17 then Long West 104 up to North 20

North Edge:  Latitude North 23

East Edge: Long West 56

South Edge: Latitude North 6

The issues are too complex to discuss here.  Generally the Carib Plate is pushed northerly by a large fragment of the Pacific Plate, the Cocos Plate, which is expanding from the East Pacific Rise.  The Cocos plate is in turn being pushed by the northward-moving Nasca Plate which is expanding to the north from the Antarctic Plate while pushing also to the east against South America from the East Pacific Rise.

The Carib Plate is also being pushed from the northeast and east directly onto the Cocos Plate by the expansion of the Atlantic Great Rift.   The Atlantic Plate  subducts under the eastern edge of the Carib Plate, thus uplifting it to form the Carib Islands, such as the Antilles, Puerto Rico, etc.   

The Cocos Plate subducts under the western edge of the Carib Plate, uplifting the Pacific side and forming a long chain of classic subduction volcanoes.  Accordingly, the Carib Plate has two major chains of classic subduction volcanoes on at least two of its opposite sides.  This is a unique feature of the Carib Plate, at least for present knowledge. 

The Cocos Plate is also sliding past the edge of the Carib Plate (Central America Western Coast) to the north where it is also subducting under North America to form the chain of volcanoes which begin with Colima and Popo and dominate Central Mexico.  As a result of this northerly and easterly movement of the Carib and Cocos Plate (relative to the Atlantic Ocean), the Carib Plate also grinds its way through Central America;

With the additional volcanism in Mexico (and more can be found in Columbia)  the Carib Plate is apparently the only tectonic plate which in encircled in a ring of  subduction volcanoes.

All this makes for a very dynamic area and indeed it is.  Carib and Cocos Subduction Volcanoes quite often comprise the most active zone in the world and several volcanoes in these zones have been in perpetual eruptions for decades.  Earthquakes are equally abundant.

The Mexican highland volcanoes and earthquakes, including Popo and Colima appear to be "singing" in concert with the whole string of Central American Carib volcanoes and indeed they probably can't avoid doing so.  Common to both is the Cocos Plate subduction. Statistically, these all group together as an exceptional compression zone region even if the definition of "Plate Margins" remains crude and in need of  considerable refinement.

Thus for planetary accounting purposes, we can group them all together statistically with Carib plate activity without distorting much, even if they do not fit strictly together in the current models of the plates. 

In essence the basics come down to this, the entire zone between the Antilles to the Pacific Ocean, from Central Mexico to Columbia, is a vast compression zone subjected to great opposing force vectors in which geologic change is occurring much more rapidly than in North America.  For simplicity sake, this zone, which includes part of the Cocos Plate and some overlap with North America and South America,  is referred to as the Carib Plate Tectonic Zone in the Earth Changes Gallery

By defining the western edge of this zone at Long. West 102, we keep the entire East Pacific Rise expansion zone out of the statistical group.  To accommodate a number of issues, the northern edge of this Carib Zone runs from the Pacific beginning with a Triple Junction near Los Cabos on Lat. North 23 through to the top of Cuba and Puerto Rico and the Eastern Carib Islands. 

This is not fully adequate because we need to include the Colima coastline in our Carib group. For this we must use a polygon definition (a way of defining more than just four simple sides for our sample).  By notching it over to 104 at North 17 and then up to North 23, we connect the ccompression zone at Colima in our statistical group which we are calling the Carib Zone.

The eastern and northern edges are carefully but arbitrarily defined as

East Edge: Long West 56

South Edge: Latitude North 6

South America

(map images do not correspond exactly with definitions)

file name:  LATAM

    * polygon=15,42,8,42,8,55,-25,55,-25,76,15,76,15,42

polygon=6,-83,-30,-83,-30,-77,-60,-77,.-60,-20,-10,-20,6,-50,6,-83

xxx edit

On the northern edge, the line which forms the southern boundrary for the CARIB tectonic zone is used.  This is Latitude North 6

This zone is simplified on the western edge along one straight Longitude of Long. West 83 to the Equator and then over to Long. West 77 and straight down to Lat. South 60.   This creates some gap between some portions the EASTPAC zone, but this gap is in a zone of ocean bottom in which there are virtually no detected or recorded eathquakes.

At the tip of South America we run into one of the most difficult zones of the planet to understand.  It appears that we have another convergence compression zone merging with a portion of the Expansion Rift which surrounds the Antarctic Tectonic Plate. We also appear to have another mini platelet, the Scotia Micro-Plate on which floats the Falkland Islands to the east of the tip  of South America.  This micro plate appears to be the product of a bit of all forms of tectonic plate activity, making a very messy modeling affair.

Between Long. West 77 and Long. West 20, it is very difficult to easily sort the phenomenon without intimate local knowledge of the zone.  Accordingly, I am forced to keep it simple and this portion of the Antarctic Tectonic Plate is dealt with as a compression zone belonging to Latin America.

Africa

(map images do not correspond exactly with definitions)

polygon=15,-20,2,0,-40,-40,40,-30,40,-30

Africa may be best considered, Like North America, a clefted continent.  It is rifting and or perhaps folding right down the center through what is known as the East African Rift.

North America has a similar cleft.  It begins in the mouth of the Mississippi and runs through the New Madrid Fault up to the St. Lawrence, from whence it runs up the Greenland passage into the Arctic.  In North America this is clearly folding and downwarping caused by compression.

In Africa, the cleft runs from South Africa, up the great Rift Valley to Ethiopia and into the Red Sea.  Along this great Rift are many of the greatest geological and scenic features of Africa.

This cleft is said to be an expansion rift.  However, this is hard to comprehend.  There should be a corresponding zone of subduction somewhere to the east or west of Africa but no chains of volcanoes can be found.  Only the Atlantic and Indian Expansion Rifts are found.  The expansionary forces of these two Rifts  should have "frozen" Africa or begun to generate folding, downwarping, and high piling of portions of the continent on north-south parallels. 

In other words, the way the geology of Africa is generally presented seems to contradict basic plate tectonic dynamics.  What is actually occurring needs careful weighing beyond my knowledge. It is impossible to categorize Africa in this Storyboard Model without a lot more detailed local familiarity. Accordingly I don't. 

Most of North Africa is defined de facto into Eurasia to capture the Mediterranean compression zone for that continent's edge.  For the remainder, we leave it a block of mystery.  A call on the ANSS database for this polygon brings in "thin" data.  Central and South Africa are tectonically not very active OR, they are not very well recorded.


Comparative Activity Charts For The Major Zones

 

Using the definitions  for the tectonic zones which are specified in detail on this webpage, quake data was queried from ANSS, USGS, and SCSN databases.  Spreadsheets models were constructed for each zone with a standard set of summarization and analysis algorithms and trend display graphs (Excel software) . 

To access charts on a zone basis, return to the Table of Contents and use the icons and titles to select the area you wish to access in detail.   Each zone has its own storyboard webpage with a display of quake activity in a variety of charts, including highly detailed near-daily intervals to permit searching for correlations with other phenomenon. 

Keep in mind that the icons in the Table of Contents will open up a full image display of the graph or map, but with no accompanying text.  To get the discussion and details which go with each chart you must click on the titles. 

In this section below, we summarize the activity of the various zones by drawing all their trend lines or statistics into combination graphs for quick comparison.

As you reflect on the numbers, keep in mind that no attempt has been made in this current modeling effort to create a database so integrated that you can sum all zone totals into a world total.  You cannot, there are overlaps, omissions in zone definition, and too much difficulty using Microsoft PC software to happily integrate all the data.

That said, the shortcomings are trivial scientifically except for the expansion rifts.  The profiles for most of the zones provide a realistic portrayal of the approximate differential levels of activity at Magnitude 4+ (1973-2007) and for even Magnitude 2+ (1991-2007)in many of the zones (within the carefully selected time frames which can be scientifically validated).

There is a major exception for the expansion rifts.  More probable than not, activity in the expansion rifts of  the Southern Hemisphere are not very well reported for activity under 4+.  Since most of the activity of the expansion rifts is "apparently" under 4+ (based on studies of the North Atlantic) the lack of this information for the Southern Hemisphere greatly limits the value of the comparisons we can currently make between the zones.

 

World Quakes 4+ Totals Distributed By Tectonic Zones 1973-2006
portrait by MWM 2007;
model source: ANSS Composite Database; world_quake_summary.xls by MWM
quakes_world4+_zonetots_1973-2007.gif

 

North America = Western, Eastern and Carib Plate Zones
Western Pacific = as defined for Japan & East Asia plus Western Pacific (Philippines Plate)

This chart totals all counts for the entire period 1973-2006 for each of 12 primary zones.  Thus the numbers sum the entire period for these zones. The selection of these zones does NOT sum to the World Total. The spreadsheet which built this graph uses a line model which also has many subsidiary zones and subtotals. 

Zones 1-8 are compression zones and the first six provide a block of good numbers.  Thus the left hand side of this chart composes a reasonable profile of comparative quake activity.  Zone 7 is mid to southern Africa and the entries for this data base are most likely "thin" from "Under-reporting".  Best to ignore it.  Zone 8 is a small fragment which composes essentially a part of Myanmar along the eastern transform fault of the Indian Plate.  It probably should be integrated with Eurasia.   I thought I would learn something if I isolated this region.  If I did learn anything, it is not apparent.

These "zones" are not called plates for a reason. They are not plates. They are not continents.  The "zones" focus on and classify the earthquake activity zones which can be seen in the world maps of quake activity. These quake activity zones generally arise between  portions of two or more tectonic plates.  Thus if we encompass entirely a certain zone, our definitions overlap portions of two or more plates.  But this does not mean we have included the entire plate of any plate.  In fact, generally we do not.

It is nearly certain that 95% of all quake activity occurs at the adjoining edges of the tectonic plates.  Thus the majority of the surface of the Earth can actually be ignored for analyzing this activity.  Gaps in the coverage of the interiors of continents mean nothing at a planetary perspective.

As can be seen, by far the greatest activity is related to Zone 5, called the South Pacific on this chart.  The area includes New Zealand, all the South Pacific Islands to the North of Australia, and all of Indonesia as well as the western edge of Australian Tectonic Plate.  It does not include the southern edge of this plate, which is summed into Antarctica.  The greater part of this activity on the northern edge is compression quake activity and most of it involves rapid subductions of the Pacific, Philippines, or Eurasian Plates. running along an east-west orientation (parallel with the Equator).  About one fourth of this activity is in the north-south subduction and slip zones on the eastern edge of the Australian Plate.

The next greatest activity is in Zone 4 which begins immediately to the north of the vast Australian plate and runs north all the way to Latitude 75 along the eastern edge of Eurasia.  This area includes the highly active areas north of Borneo, through the Philippines and Southeast Asia to Taiwan.   This zone then continues from Okinawa through Japan up to Latitude North 75, from the International Dateline through Eastern Siberia and Manchuria into the China Sea. The greater part of this activity involves subduction of the Pacific Plate and generally the subduction zones run north-south. There is also some continental activity in Northern China/Siberia.

As can be seen, the western arc of the Pacific Rim easily accounts for the greatest amount of quake activity in the world, all mainly driven by the fast expansion rifts south of Australia (Zone 9) and to the west of South America in the East Pacific Rift (Zone 10).

From this set of numbers, one could easily think that the expansionary impulse in the North Atlantic must be the prime mover which is producing the high level of activity in the Western and Southern Pacific.  One could conceive that Eurasia is being pushed onto the Pacific Plate. But the maps which show us the banding of the ages of the ocean bottoms completely contradicts this idea. So does modern geodesy which uses a variety of means to establish the relative motions of portions the crust.  All the data and scientific literature appear to converge on the East Pacific as the most active spreader, with the Pacific Plate moving from it far more rapidly than from any other expanding rift.

Faced with this, do the numbers for the Rifts make sense compared with levels of activity in the western arc of the Pacific Rim? Doubtless, no.  If the main line of scientific literature is correct, the numbers for the Pacific and Indian Ocean rifts must be higher.  Thus there is no reason to believe the numbers  for Zones 7 through 12, with the possible exception of the Atlantic Rift (Zone 11).  The North Atlantic appears to be recorded well even down to 2.0.  But the South Atlantic probably is not as well recorded.  

One might explore the idea that these rifts expand much more "silently", in much smaller sized quakes than the other rifts. The Earth is diverse enough that there could be some truth in that notion but unfortunately we have no way to check on it.  No activity under Magnitude 4.0 is being recorded for  the East Pacific Rift, a severe omission which planetary level scientists must address.  We have the same problem with Zone 9, the Antarctic Rift to the south of Australia.

World Quakes 4+ Percentage Distribution By Tectonic Zones 1973-2006
portrait by MWM 2007;
model source:  ANSS Composite Catalog; world_quake_summary.xls by MWM
quakes_world4+_zone_percents_1973-2007.gif

 

North America = Western, Eastern and Carib Plate Zones
Western Pacific = as defined for Japan & East Asia plus Western Pacific (Philippines Plate)

 
This chart summarizes the hard count numbers into relative percentages.  Eurasia and the western arc of the Pacific Rim of Fire (including the portions connected to Australia) create 64% of the Earth's quakes.  The Western Hemisphere (including the Aleutians to the International Dateline) produces 26%.  In the following chart you will see that Western North America (not including Alaska) produces a mere 2% of the world total.
 
 

Pacific Rim Quakes 4+ Percentage Distribution By Tectonic Zones 1973-2006
portrait by MWM 2007;
model source:  ANSS Composite Catalog; world_quake_summary.xls by MWM
quakes_world4+_Rim_zone_percents_1973-2007.gif

This chart provides a little different organization of the zone areas to focus on specific regions around the Pacific Rim of Fire.   This was organized partly to break down "South Pacific" into its constituent sub-zones, Northern Australia, Western Australia, and a statistical area called in this Gallery "New Zealand" (which in retrospect was not a good label).

Western Pacific = as defined for Japan & East Asia plus Western Pacific (Philippines Plate)
New Zealand NE = International Dateline - to Long. West 165, Lat. South 50 - Lat. North 10
This definition of "New Zealand" is in retrospect a poor choice, essentially it is the area north of New Zealand nearly halfway through the northern tropics and all to the east to encompass most of the remainder of the South Pacific Islands which are associated with the Australian Tectonic Plate. Unfortunately the inappropriateness of this label was not realized until too late in the draft to attempt to revise the charts and text which connect with it.  In a later update version of the Gallery, definitions of this area should be made more sophisticated to deal with the microplates to the north of Australia and the complex eastern edge which is formed by the New Zealand Islands.

These Pacific Rim zones are reported in ways  somewhat differently than in the previous charts to bring certain patterns into view.  There are four patterns of interest.

1.  North America has been broken down to separate Western North America (Great Plains to the Pacific) from the Carib Plate and from Eastern North America (Mississippi to Newfoundland).  North America as whole in a previous chart was summarized at 8%.  In this chart we can see that two thirds of this activity is in the Carib Plate (6% of world total).  Surprisingly, the western portion of North America, despite the hyper-activity of Southern California in smaller quakes, is only 2% of the world total. By simple arithmetic, we can conclude that the eastern portion of North America is very quiet at the level of 4+ movements.

2.  Two well defined  areas in the Pacific, the Northern Arc (24%) and the Southern Arc of the Pacific Rim (32%), produce about 55% of the world total quake activity.  At opposite ends of the Pacific, two subduction rifts in the same quadrant of the Earth are being battered by the Pacific Ocean Plate to produce a majority of the world's 4+ quakes.  In the Southern Arc, Australia and the New Zealand Zone, including also the Fiji, Tonga, and Solomon Island groups,  produce 32% of the world's quake activity.  In the Northern Arc of the Pacific Rim, Japan, and Eastern Siberia through the Aleutians to the Great Peninsula of Alaska produce 24%. 

3.  Using the International dateline as a point of reference because it bisects the Northern Arc,   the Carib and South American Plates  beat out 13% of total world quakes at nearly a 90 degree angle to the mid-point of the Northern Arc. About 80 degrees to the west of the mid-point, the Australian Plate margin slips past the edge of Eurasia along the extremely active western coast of Sumatra.  Within these Arcs and Zones, by far the greater part of the world's major quake activity can be found.

4.  In another way of seeing it, the southwestern Pacific Rim of Fire produced 40% of the current world total movement while Japan and all of Eurasia produce about 24%.  The southwestern Rim area (mainly the northern edge of Australia and the southern edge of the Philippine Plate) appears to be producing most of this 40% through a band of what may be realistically defined as a special group of plate fragments  sitting on or adjacent to the equator. 

QUITE CLEARLY, THE SOUTHWESTERN PACIFIC IS WHERE THE EARTH'S CRUST IS BREAKING UP THE MOST RAPIDLY FROM COMPRESSION FORCES.  This South Pacific breakup is induced by collision between the northeastern movement of the Australian Plate and the northwestern movement of the Pacific Plate.  These vast collisions are producing the band of fragments which have broken off the Pacific Plate between the Pacific Plate on the east, Eurasia on the west, and Australia on the south.

At nearly 180 degrees removed, the most active expansion zone, the East Pacific Rift, is pushing Pacific Plate Fragments apart more rapidly than in any other zone.  At about a 170 degree angle from the East Pacific Rift (as figured by traveling to the east)  one finds the spreading rift of Antarctica/Bharati.  At this expansion point, the Australian Tectonic Plate is about the second fastest Tectonic Plate as it move towards the northeast.

These facts correlate together very well the level of recorded earthquake activity with the inferred age of the ocean bottom, with current estimated spreading rates, with the simple geometry of the Earth,  and with the actual tectonics of its crustal plates or fragments.  In this composite correlation, we can clearly see from where the most active subduction zones get their above average push.

The main thing missing in the equation is adequate record-keeping of the quakes in the Great Rift of the Southern Hemisphere.  When this become a reliable norm, geophysicists may be able to advance clever and sophisticated energy and stress calculations to build the basis for truly predicting the rise and fall of seismic activity around the Pacific Rim.

Comparative Trends In The Major Tectonic Zones
portrait by MWM
model source:  ANSS Composite Catalog; world_quake_summary.xls by MWM
quakes4+_compare_trends_majorzones_1973-2007
 

This chart is for comparing average daily frequencies in the various zones to gain a sense of perspective about the Earth's tectonic trends.  We can see immediately in this chart that Japan and the South Pacific (Australia and New Zealand Zone) are the main source of the accelerating trend, with by far the greatest driver being in the South Pacific. 

ACCORDINGLY, IS IT NOT OBVIOUS THAT THE EARTH IS MOST ACTIVE IN THE WESTERN ARC OF THE PACIFIC RIM,  MOST ESPECIALLY IN THE SOUTHERN HALF?

Not much trend seems evident in this chart for the other zones.   But their flat lines are forced by extreme compression of their scale.  When trend lines are drawn for the other areas in scales which suit the zone, many trends of acceleration appear.  These, however,  are not as dramatic.

Important Note:  The daily average for 2007 was computed in May 2007.  Since then the daily average has increased once again, thus the dip shown for 2007 is likely a seasonal type of fluctuation.

Compare with Wobble:  Notice that the trend line of world activity appears to increase during each Wobble MIN phase.  Notice also that since the late 1980's any spike of increase in earthquake activity never completely returns to former averages. The daily average falls a bit and then keeps pushing higher and higher, two steps up for every step down.  The last major increase in the global trend is clearly anomalous even to this correlation.  The latest increase in quake activity, during the recently past Wobble MIN phase, is much larger than has ever before been observed.  There is no explanation for this large change in the earth.

Compare with Declination.  There is no correlation with earthquakes in this  global trend chart through the entire period.  There is a definite correlation between Lunar Declination (angle of the Moon's orbit) and the Wobble MAX cycle. The Wobble Spiral appears to beat at the rate of three Wobble MAX cycles to one Saros Cycle.  See the Wobble Storyboard.

NOTE ABOUT  USING THESE NUMBERS TO COMPARE WITH CURRENT QUAKE LISTS:

Unfortunately one cannot use these numbers to analyze breaking news lists or for any list of quakes less than about 30 days old.  Many of the smaller quakes below about 5.o are not listed until days or even weeks after the fact.  Even the large quakes often have their numbers changed several days after the event.  To obtain good numbers, one must accept at least a 30 day lag.  That said, one can, however, generally use the counts for comparisons for all 6+ quakes about 72 hours after the event.  These large numbers are frequently revised but generally this happens very quickly after large events because the information is in high demand.


Summary of Major Observations

 

organization of perspective into real zones immeidately demonstrates many correlations and truths.

Enormous numbers of earthquakes signal all of this  activity the length and breadth of these tectonic collision zones.  This collision activity "sounds" in general to be substantially "louder" than the expansion activity.  By far, most of the seismic activity at Class 4+ is in these contracting subduction zones.  The expansion rifts are more silent with most of their activity well under Class 4. 

The map above which displays the Class 7+ quakes reveals clearly that large quakes in the oceanic Great Rift are extremely rare.  Thus we can readily observe that expansion activity is in smaller magnitudes than compression activity.  This may be consistently true everywhere but we cannot exactly take it as a given at this time. Too much of the Great Rift is not documented for seismic activity below Class 4.  We need everything recorded to really understand the ratios and know their truths.

It may be that most of the expansion activity in the Great Rift is in the magnitude range of 1 to 3, very little of which is being recorded at the present time.  This is a hugely important major scientific problem which needs to be resolved as quickly as possible.  Global Warming "scare money" should be applied to a program of intensive seismic and temperature monitoring of the entire oceanic Rift system.   This is of far greater importance than missions to Mars or futile efforts to abate CO2 production.

 

The second vector is Earth's Wobble.  The Wobble is a 14 month cycle and a seven year cycle of constant change in the location of the poles of the Spin Axis.  During these cycles, the wobble expands and contracts in size.  These changes in the Wobble exert a significant regular influence on how and how much the Earth shifts its shape.  This influence is readily seen in many of the earthquake graphs.  Earthquake activity can often be seen to increase and decrease in tandem with the rhythm of the Earth's expanding and contracting wobble spirals.

 

In other, more specific terms, we are living through a cosmically-driven trend of tectonic change in the Earth.  The accumulating rate of acceleration in the drift of the location of the Spin Axis  is driving the observable Global Trends in earthquake activity (four to fivefold during the past fifty years for activity at magnitude 2.5 or greater)  and volcanic activity (threefold during the past fifty years).  This increase in tectonic motion and heat release is in turn driving most climate change and Global Warming phenomenon.

The next greatest activity is in Zone 4 which begins immediately to the north of the vast Australian plate and runs north all the way to Latitude 75 along the eastern edge of Eurasia.  This area includes the highly active areas north of Borneo, through the Philippines and Southeast Asia to Taiwan.   This zone then continues from Okinawa through Japan up to Latitude North 75, from the International Dateline through Eastern Siberia and Manchuria into the China Sea. The greater part of this activity involves subduction of the Pacific Plate and generally the subduction zones run north-south. There is also some continental activity in Northern China/Siberia.

As can be seen, the western arc of the Pacific Rim easily accounts for the greatest amount of quake activity in the world, all mainly driven by the fast expansion rifts south of Australia (Zone 9) and to the west of South America in the East Pacific Rift (Zone 10).

From this set of numbers, one could easily think that the expansionary impulse in the North Atlantic must be the prime mover which is producing the high level of activity in the Western and Southern Pacific.  One could conceive that Eurasia is being pushed onto the Pacific Plate. But the maps which show us the banding of the ages of the ocean bottoms completely contradicts this idea. So does modern geodesy which uses a variety of means to establish the relative motions of portions the crust.  All the data and scientific literature appear to converge on the East Pacific as the most active spreader, with the Pacific Plate moving from it far more rapidly than from any other expanding rift.

Faced with this, do the numbers for the Rifts make sense compared with levels of activity in the western arc of the Pacific Rim? Doubtless, no.  If the main line of scientific literature is correct, the numbers for the Pacific and Indian Ocean rifts must be higher.  Thus there is no reason to believe the numbers  for Zones 7 through 12, with the possible exception of the Atlantic Rift (Zone 11).  The North Atlantic appears to be recorded well even down to 2.0.  But the South Atlantic probably is not as well recorded.  

One might explore the idea that these rifts expand much more "silently", in much smaller sized quakes than the other rifts. The Earth is diverse enough that there could be some truth in that notion but unfortunately we have no way to check on it.  No activity under Magnitude 4.0 is being recorded for  the East Pacific Rift, a severe omission which planetary level scientists must address.  We have the same problem with Zone 9, the Antarctic Rift to the south of Australia.

 

ACCORDINGLY, IS IT NOT OBVIOUS THAT THE EARTH IS MOST ACTIVE IN THE WESTERN ARC OF THE PACIFIC RIM,  MOST ESPECIALLY IN THE SOUTHERN HALF?

Not much trend seems evident in this chart for the other zones.   But their flat lines are forced by extreme compression of their scale.  When trend lines are drawn for the other areas in scales which suit the zone, many trends of acceleration appear.  These, however,  are not as dramatic.

 

Notice that the trend line of world activity appears to increase during each Wobble MIN phase.  Notice also that since the late 1980's any spike of increase in earthquake activity never completely returns to former averages. The daily average falls a bit and then keeps pushing higher and higher, two steps up for every step down.  The last major increase in the global trend is clearly anomalous even to this correlation.  The latest increase in quake activity, during the recently past Wobble MIN phase, is much larger than has ever before been observed.  There is no explanation for this large change in the earth.

Two well defined  areas in the Pacific, the Northern Arc (24%) and the Southern Arc of the Pacific Rim (32%), produce about 55% of the world total quake activity.  At opposite ends of the Pacific, two subduction rifts in the same quadrant of the Earth are being battered by the Pacific Ocean Plate to produce a majority of the world's 4+ quakes.  In the Southern Arc, Australia and the New Zealand Zone, including also the Fiji, Tonga, and Solomon Island groups,  produce 32% of the world's quake activity.  In the Northern Arc of the Pacific Rim, Japan, and Eastern Siberia through the Aleutians to the Great Peninsula of Alaska produce 24%. 

3.  Using the International dateline as a point of reference because it bisects the Northern Arc,   the Carib and South American Plates  beat out 13% of total world quakes at nearly a 90 degree angle to the mid-point of the Northern Arc. About 80 degrees to the west of the mid-point, the Australian Plate margin slips past the edge of Eurasia along the extremely active western coast of Sumatra.  Within these Arcs and Zones, by far the greater part of the world's major quake activity can be found.

4.  In another way of seeing it, the southwestern Pacific Rim of Fire produced 40% of the current world total movement while Japan and all of Eurasia produce about 24%.  The southwestern Rim area (mainly the northern edge of Australia and the southern edge of the Philippine Plate) appears to be producing most of this 40% through a band of what may be realistically defined as a special group of plate fragments  sitting on or adjacent to the equator. 

QUITE CLEARLY, THE SOUTHWESTERN PACIFIC IS WHERE THE EARTH'S CRUST IS BREAKING UP THE MOST RAPIDLY FROM COMPRESSION FORCES.  This South Pacific breakup is induced by collision between the northeastern movement of the Australian Plate and the northwestern movement of the Pacific Plate.  These vast collisions are producing the band of fragments which have broken off the Pacific Plate between the Pacific Plate on the east, Eurasia on the west, and Australia on the south.

At nearly 180 degrees removed, the most active expansion zone, the East Pacific Rift, is pushing Pacific Plate Fragments apart more rapidly than in any other zone.  At about a 170 degree angle from the East Pacific Rift (as figured by traveling to the east)  one finds the spreading rift of Antarctica/Bharati.  At this expansion point, the Australian Tectonic Plate is about the second fastest Tectonic Plate as it move towards the northeast.

These facts correlate together very well the level of recorded earthquake activity with the inferred age of the ocean bottom, with current estimated spreading rates, with the simple geometry of the Earth,  and with the actual tectonics of its crustal plates or fragments.  In this composite correlation, we can clearly see from where the most active subduction zones get their above average push.

The main thing missing in the equation is adequate record-keeping of the quakes in the Great Rift of the Southern Hemisphere.  When this become a reliable norm, geophysicists may be able to advance clever and sophisticated energy and stress calculations to build the basis for truly predicting the rise and fall of seismic activity around the Pacific Rim.

This chart summarizes the hard count numbers into relative percentages.  Eurasia and the western arc of the Pacific Rim of Fire (including the portions connected to Australia) create 64% of the Earth's quakes.  The Western Hemisphere (including the Aleutians to the International Dateline) produces 26%.  In the following chart you will see that Western North America (not including Alaska) produces a mere 2% of the world total.

 

 


 

uakes4+_daily_

 

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