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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:
-
in the oceans where the expansion rifts are pushing the
tectonic plates and
continents apart, and
-
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
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
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
(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.
|
Digital
Elevation Map From NOAA
