BAROMETER ERUPTERS:
About 20 to 30 volcanoes each year are very nearly in a continuous state of eruption.  The active volcanoes which are continuously erupting change their names only very slowly.  This means there is some turnover in the list, but it is generally at a low rate.  I have not computed it for yearly averages but it is likely in the range of about 15%.  

Most Active Zones:

Australian Tectonic Plate (northern edge)

Hawaii

Italy  - another vigorous round began April 30

Japan - Kamchatka Peninsula & Northern Arc of Rim of Fire (Aleutians-Alaska)

Western Americas - Mexico to Peru
 

Most Active Volcanoes:

Continuous Erupters:  activity continues in all

Kilauea, Hawaii: long lava flows into the Pacific Ocean - slowing now

Erebus, Ross Bay, Antarctica: lava lake, strombolian explosions

Stromboli, north of Etna: lava fountains, strombolian explosions

Yasur (Lighthouse of the Pacific, Vanuatu Island: lava lake, fountains, strombolian explosions

Arenal, Costa Rica: lava fountains and strombolian explosions
 

Nearly Continuous Erupter:

Etna, Sicily:  sleeping at the moment

A few on the Carib Plate are upsurging.

Summary of Yellowstone Uplift

From the INTLVRC: http://www.intlvrc.org/restless.htm

As of the 9th of November, the Yellowstone Volcano Observatory (YVO), reported that the November 9, 2007 issue of Science Magazine features an article, Accelerated uplift and magmatic intrusion of the Yellowstone Caldera, 2004 to 2006, by YVO scientists from the University of Utah and USGS. The lead author, Wu-Lung Chang is a Post-doctoral associate with Dr. Robert B. Smith, YVO Coordinating Scientist at the University of Utah. Chang specialises in use of the Global Positioning System (GPS) to measure very small movements of the Earth's crust. Using GPS and another satellite-based technique (InSAR), the authors find that parts of the Yellowstone Caldera rose as much as 7 cm (~3") per year during the period 2004-2006. The uplift is most noticeable at the White Lake GPS station, as has been discussed in YVO's monthly YVO updates during the past year. As of late October 2007, the total uplift since 2004 at that location is about 17 cm (~7"). Chang and his colleagues credit the relatively rapid rise to recharge of magma into the giant magma chamber that underlies the Yellowstone Caldera. They also used numerical modeling to infer that the magma intruded about 10 km (6 miles) beneath the surface.

North of this region of uplift, another area at Yellowstone has moved downward over the past three years. This north rim uplift anomaly (NUA) had risen during the period 1996-2003, when the rest of the caldera had subsided. The activity was featured in a 2006 article in Nature Magazine with lead author Charles Wicks, one of the co-authors on the new article in Science Magazine. Chang and others hypothesise that magma input after 2004 caused fracturing of the crust that resulted in release of hydrothermal fluids from the north rim area. The loss of fluid pressure then resulted in deflation, or subsidence of the ground surface.

Interestingly, the Yellowstone caldera has remained seismically quiet during the past three years of uplift. An earlier article on the YVO website, Satellite Technologies Detect Uplift in the Yellowstone Caldera, provides context on the techniques used to study these movements. The new activity, though more rapid than those previously measured at Yellowstone, is not unprecedented at large calderas around the globe. Given the absence of large earthquakes, earthquake swarms and anomalous behaviour of Yellowstone's hydrothermal system (its geysers, mud pots and fumaroles), all of us find little indication that the volcano is moving towards an eruption. At this time, volcanic eruptions and hydrothermal explosions remain an unlikely possibility. Given the geologic history of the area, it is likely that the current period of uplift will cease, to be followed by another cycle of subsidence. When this might happen, though, is unknown.

During the month of October 2007, 34 earthquakes were located in the Yellowstone Region. The largest of these shocks was a magnitude 2.1 on October 17, 2007 at 0639hrs MDT, located about 26 miles southeast of West Thumb, WY. There were no swarms and no earthquakes were reported felt during October. Earthquake activity in the Yellowstone region is at low background levels.

Ground Deformation Summary: Through October 2007, continuous GPS data show that most of the Yellowstone caldera continued moving upward at similar to slightly lower rates as the past year. The maximum measured ground uplift over the past 36 months is ~17 cm at the White Lake GPS station. An example can be found at: http://pboweb.unavco.org/shared/scripts/stations/?checkkey=WLWY&sec=timeseries_plots&timeseries=raw .

 The general uplift of the Yellowstone caldera is scientifically interesting and will continue to be monitored closely by YVO staff.

The colour code at Yellowstone is currently at GREEN.

Ancient "Supervolcano" Rocked Washington State

Richard A. Lovett
for National Geographic News
February 6, 2007

Tahoma (Rainier so-called by crazy white men) could easily become the same kind of event.