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Alaska Volcano Observatory

Alaska Volcano ObservatoryCurrent Status ReportMonday, September 15, 2008 11:34 AM AKDT (19:34 UTC)

KASATOCHI VOLCANO
52°10'9" N 175°30'41" W, Summit Elevation 1030 ft (314 m)
Current Aviation Color Code: YELLOW
Current Volcano Alert Level: ADVISORY

Low level seismicity at Kasatochi continues. Intermittent power outages are affecting AVO's seismic networks in the Kasatochi area. Satellite views were cloudy today.


Kasatochi Volcano does not have a seismic network, thus AVO depends on networks on neighboring islands to monitor earthquake activity there. For this reason, low-level seismicity may not be detected. Renewed volcanic activity is possible at any time with little or no warning.

OKMOK VOLCANO
53°23'49" N 168°9'58" W, Summit Elevation 3520 ft (1073 m)
Current Aviation Color Code: YELLOW
Current Volcano Alert Level: ADVISORY

Seismicity at Okmok volcano continues at low levels. Satellite views were cloudy today.

Although the level of seismicity has declined, it is possible for vigorous ash emissions to resume at any time.

CLEVELAND VOLCANO
52°49'20" N 169°56'42" W, Summit Elevation 5676 ft (1730 m)
Current Aviation Color Code: YELLOW
Current Volcano Alert Level: ADVISORY

Clouds obscure Cleveland volcano in satellite and web camera views. AVO received no reports of activity at the volcano.

AVO monitors Cleveland Volcano with satellite imagery as weather allows. The lack of a real-time seismic network at Cleveland means that AVO is unable to track local earthquake activity related to volcanic unrest. Short-lived explosions of ash that could exceed 20,000 ft above sea level can occur without warning and may go undetected on satellite imagery.

OTHER ALASKA VOLCANOES

Seismic activity is monitored in real time at 30 volcanoes in Alaska. Satellite images of all Alaskan volcanoes are analyzed daily for evidence of ash plumes and elevated surface temperatures. Some volcanoes may currently display anomalous behavior but are not considered to be at a dangerous level of unrest. Augustine, Iliamna, Redoubt, Wrangell, Gareloi, Great Sitkin, Makushin, Fisher, Shishaldin, Isanotski, Pavlof, Veniaminof, Ugashik-Peulik, Griggs, Snowy, Fourpeaked, Aniakchak, Tanaga, Kanaga, Akutan, Westdahl, Dutton, Ukinrek Maars, Martin, Mageik, Trident, Katmai, Novarupta, Spurr, and Korovin volcanoes are in color code GREEN and volcano alert level Normal. All are at or near normal levels of background seismicity. AVO did not detect ash plumes or significant elevated surface temperatures in the vicinity of any volcano.

Please see http://www.avo.alaska.edu/color_codes.php for complete definitions of Aviation color codes and Volcano alert levels.

VOLCANO INFORMATION ON THE INTERNET: http://www.avo.alaska.edu
RECORDING ON THE STATUS OF ALASKA'S VOLCANOES (907) 786-7478

CONTACT INFORMATION:
Tom Murray, Scientist-in-Charge, USGS
tlmurray@usgs.gov (907) 786-7497

Steve McNutt, Coordinating Scientist, UAF
steve@giseis.alaska.edu (907) 474-7131

The Alaska Volcano Observatory is a cooperative program of the U.S. Geological Survey, the University of Alaska Fairbanks Geophysical Institute, and the Alaska Division of Geological and Geophysical Surveys.

CASCADES VOLCANO OBSERVATORY WEEKLY UPDATE
Friday, September 12, 2008 11:55 PDT (Friday, September 12, 2008 18:55 UTC)

Cascade Range Volcanoes
Volcano Alert Level: NORMAL
Aviation Color Code: GREEN

NOTICE: Mount St. Helens has been at Volcano Alert Level NORMAL and Aviation Color Code GREEN for the past month; therefore, we are migrating from a Mount St. Helens weekly update to a Cascade Range weekly update. As long as all Cascade Range volcanoes are at Normal and Green, we will continue to issue Cascade Range weekly updates. If a Cascade Range volcano shows signs of unrest, we will issue an update for that particular volcano.

Activity Update: All volcanoes in the Cascade Range are at normal levels of background seismicity. These include Mount Baker, Glacier Peak, Mount Rainier, Mount St. Helens, and Mount Adams in Washington State; Mount Hood, Mount Jefferson, Three Sisters, Newberry Volcano, and Crater Lake, in Oregon; and Medicine Lake, Mount Shasta, and Lassen Peak in northern California.

Recent Observations: Volcano seismicity at Mount St. Helens and elsewhere has remained quiet. Field work this week at Mount Rainier included installation of two long term monitoring sites, deformation survey work, and geologic sampling. At Crater Lake, two new seismic monitoring sites were installed.



The U.S. Geological Survey and University of Washington continue to monitor these volcanoes closely and will issue additional updates and changes in alert level as warranted.

For additional information, background, images, and other graphics: http://vulcan.wr.usgs.gov
For seismic information on Oregon and Washington volcanoes: http://www.pnsn.org/WEBICORDER/PNSN/welcome.html
For seismic information on California volcanoes: http://earthquakes.usgs.gov/eqcenter/recenteqsus/Maps/special/California_Nevada.php
For a definition of alert levels: http://vulcan.wr.usgs.gov/Volcanoes/Cascades/CurrentActivity/volcano_warning_scheme.html
For a webcam view of Mount St. Helens: http://www.fs.fed.us/gpnf/volcanocams/msh/
Telephone recordings with the latest update on Mount St. Helens and phone contacts for additional information can be heard by calling: (360) 891-5180.

HAWAIIAN VOLCANO OBSERVATORY DAILY UPDATE
Monday, September 15, 2008 07:43 HST (Monday, September 15, 2008 17:43 UTC)

KILAUEA VOLCANO (CAVW#1302-01-)
19.42°N 155.29°W, Summit Elevation 4091 ft (1247 m)
Volcano Alert Level: WATCH
Aviation Color Code: ORANGE

This report on the status of Kilauea volcanic activity, in addition to maps, photos, and webcam images (available using the menu bar above), was prepared by the USGS Hawaiian Volcano Observatory (HVO). Hawai`i Volcanoes National Park status can be found at http://www.nps.gov/havo/ or 985-6000. Hawai`i County Viewing Area status can be found at http://www.lavainfo.us or 961-8093.

Activity Summary for last 24 hours: Sulfur dioxide emission rates from both the Halema`uma`u and Pu`u `O`o vents remain high, returning trade winds are again blowing the gases to the southwest. Lava continues to flow through tubes originating at the east rift eruption site and is entering the ocean west of Kalapana; satellite thermal anomalies suggest surface flow activity on the coastal plain.

Last 24 hours at Kilauea summit: Yesterday, light and variable winds caused the plume direction to fluctuate; it remained white and lazy but was not very visible because the summit was quite foggy. Glow from the Halema`uma`u vent overnight was so weak that it was barely recorded by the webcam. This morning, the summit has a light haze and the plume from the Halema`uma`u vent is ascending before being blown southwest over the Ka`u Desert by strengthening trade winds. Just after 7 am, the plume turned brown as the result of a couple of local earthquakes.

This morning's tephra collection returned a much smaller yield than previously days, probably due to the weak winds of the past few days. The contents were still dominated by glassy ash. Some rock impact, or clatter, sounds were heard but the gas rushing noises were subdued.

Sulfur dioxide emission rates remained elevated and variable. The most recent average measurement was 800 tonnes/day on September 11, compared to a pre-2008 background rate of 150-200 tonnes/day. GOES-WEST satellite images show winds blowing the plumes from Halema`uma`u and Pu`u `O`o to the south-southwest. The Halema`uma`um plume continued along the coast. The returning trades should allow resumption of emission rate measurements this week.

The summit tiltmeter network and GPS stations spanning the summit caldera recorded no significant inflation or deflation.

Seismic tremor has been at steady moderate levels. Eight earthquakes were located beneath Kilauea or nearby, including 6 beneath the southern summit caldera. The number of RB2S2BL earthquakes beneath Halema`uma`u Crater decreased to background values of less than 40/d.

Last 24 hours at the middle east rift zone vents and flow field: Magma continues to degas through Pu`u `O`o Crater. The most recent sulfur dioxide measurement of 1,700 tonnes/day on September 8 is near background levels for this vent over the past 25.5 years. Weak incandescence was observed within western and central part of the crater overnight.

The tiltmeter on the north side of Pu`u `O`o recorded accelerated deflation overnight and deflation over the past week. GPS stations spanning the crater continued to record contraction. Seismic tremor levels at Pu`u `O`o and the TEB vent increased slightly to a couple of tremor bursts before the levels dropped about 50% after 4:30 am this morning.

Lava from the TEB vent and the complex of rootless shields continued to flow through tubes to the ocean. No incandescence was observed from the rift zone to the top of the pali above the abandoned Royal Gardens subdivision overnight. A small thermal anomaly appeared in the GOES-WEST satellite imagery before 4 am this morning on the coastal plain suggesting surface flow activity. GOES-WEST imagery also shows a steam plume from the ocean entry at Waikupanaha demonstrating that lava continues to enter the ocean.

Definitions of terms used in the update:

DOH air quality monitoring: see Hawai`i State Department of Health Air Quality website http://hawaii.gov/doh/air-quality/index.html .

bomb: lava fragment ejected into the air while molten acquiring aerodynamic shapes in flight; the term is restricted to pieces larger than 6.4 cm (2.5 in.). See http://volcanoes.usgs.gov/Products/Pglossary/bomb.html

hybrid, or explosion, seismic signals: complex earthquakes that are a hybrid of different signals. They start as a high frequency earthquake, similar to typical rock-breaking or rock fall events, that transitions to very long, 20-30 second, period (VLP) oscillations that continue for several minutes. At HVO, we observed these signals with the four small Halema`uma`u explosive eruptions in March, April, and August 2008. Several more similar signals, some as strong as the explosion signals associated with the four explosive eruptions, have been recorded without obvious evidenceof surface eruption such as rock fragments or other debris.

MODIS satellite: a NASA satellite pair, Aqua and Terra, which passes over Hawai`i twice a day. During daylight hours, the images are taken at about 11 am and 2 pm H.s.t. This imagery can be viewed about 3-5 hours after acquisition at http://rapidfire.sci.gsfc.nasa.gov/subsets/?subset=AERONET_Mauna_Loa.

GOES-WEST satellite: a geostationary NOAA satellite used most often for weather tracking. Images are typically acquired every 15 minutes. The loop http://www.ssd.noaa.gov/VAAC/kilauea/sloop-vis.html is posted by the Washington DC Volcanic Ash Advisory Center for the purpose of tracking emissions from Hawai`i volcanoes. The imagery automatically switches from infrared at night to visual during the day. Recently, it has been useful for tracking volcanic gas emissions from Halema`uma`u, Pu`u `O`o, and the Waikupanaha ocean entry during the day and hot lava flows at night.

Volcano Watch: weekly newspaper-like article written by HVO scientists on a volcano topic of interest. These articles are usually printed in the Sunday editions of the Hawai`i Island newspapers Hawaii Tribune Herald and West Hawaii Today. More than 800 of these articles have been written and are archived on the HVO website (menu at the bottom of the homepage hvo.wr.usgs.gov).

VLP seismic tremor: seismic tremor is continuous ground vibrations simultaneously at many different frequencies. VLP is a very long period or very low frequency component which, at the Halema`uma`u vent, has a period of 20-30 seconds or a frequency of 0.03-0.05 cycles per second (Hertz or Hz).

RB2S2BL earthquakes: earthquakes that were recorded but too small to be located. These quakes have magnitudes less than 1.7 and may only be recorded on one or two seismometers. Recording at a minimum of 4 seismometer sites is required to locate an earthquake.

wink: an abrupt shutting off of incandescence at a vent lasting for several minutes. At the Halema`uma`u vent, winks usually start with or immediately follow a small, local earthquake. The diminishment of incandescence is due to the plume changing from translucent to opaque with rock dust.

tonne: metric unit equal to 1,000 kilograms, 2,204.6 lbs, or 1.1 English tons.

microradian: a measure of angle equivalent to 0.000057 degrees.

ppm: parts-per-million; 10,000 ppm = 1 %.

littoral cone: usually small cones built near active ocean entries; the cones are constructed of tephra from steam explosions that are sometimes produced when 1,150 degree C lava enters the 25 degree C ocean.

incandescence: the production of visible light from a hot surface. The color of the light is related to the temperature of the surface. Some surfaces can display dull red incandescence at temperatures as low as 430 degrees Centigrade (806 degrees Fahrenheit). By contrast, molten lava displays bright orange to orange-yellow light from surfaces that are hotter than 900 degrees C (1,650 degrees F).

tephra: all material deposited by fallout from an eruption-related plume, regardless of size.

ash: tephra less than 2 mm (5/64 inches) in size.

TEB: Thanksgiving Eve Breakout, the designation used for lava flows that started with a breakout on November 21, 2007.

DI tilt event: DI is an abbreviation for 'deflation-inflation' and describes a volcanic event of uncertain significance. DI events are recorded by tiltmeters at Kilauea summit as an abrupt deflation of up to a few microradians in magnitude lasting several hours to 2-3 days followed by an abrupt inflation of approximately equal magnitude. The tilt events are usually accompanied by an increase in summit tremor during the deflation phase. A careful analysis of these events suggests that they may be related to changes in magma supply to a storage reservoir at less than 1 km depth, just east of Halema`uma`u crater. Usually, though not always, these changes propagate through the magma conduit from the summit to the eruption site, as many of the DI events at Kilauea summit are also recorded at a tiltmeter at Pu`u `O`o, delayed by 1-2 hours. DI events often correlate with lava pulses and/or pauses in the eruption at the Pu`u `O`o/July 21/TEB vents.


Maps, photos, webcam views, and other information about Kilauea Volcano are available at http://volcano.wr.usgs.gov/kilaueastatus.php. A daily update summary is available by phone at (808) 967-8862.

A map with details of earthquakes located within the past two weeks can be found at http://tux.wr.usgs.gov/

A definition of alert levels can be found at http://volcanoes.usgs.gov/2006/warnschemes.html

LONG VALLEY OBSERVATORY CURRENT STATUS REPORT
Monday, September 15, 2008 10:13 PDT (Monday, September 15, 2008 17:13 UTC)

LONG VALLEY VOLCANIC CENTER VOLCANO (CAVW#1203-14-)
37.70°N 118.87°W, Summit Elevation 11122 ft (3390 m)
Volcano Alert Level: NORMAL
Aviation Color Code: GREEN

Two small magnitude earthquakes (both M=1.4) were detected in the vicinity of Long Valley caldera since the last update at 12:09 PM (PDT) on Sunday September 14. Both of the events were located outside the caldera in the Sierra Nevada.

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The Long Valley Observatory (LVO) monitors and studies earthquakes, ground deformation, degassing, and other types of geologic unrest in and around the Long Valley Caldera. The 15 by 30 km Long Valley Caldera was formed during an eruption 760,000 years ago and is located 20 km south of Mono Lake along the east side of the Sierra Nevada in east-central California. There have been multiple smaller eruptions since the caldera-forming eruption with the most recent occurring 250 years ago in Mono Lake at the north end of Mono-Inyo Craters volcanic chain. LVO is one of the five USGS Volcano Observatories that monitor volcanoes within the United States for science and public safety.

NORTHERN MARIANA ISLANDS WEEKLY UPDATE
Friday, September 5, 2008 08:04 MPT (Thursday, September 4, 2008 22:04 UTC)

ANATAHAN VOLCANO (CAVW#0804-20=)
16.35°N 145.67°E, Summit Elevation 2592 ft (790 m)
Volcano Alert Level: ADVISORY
Aviation Color Code: YELLOW

Report prepared by the U.S. Geological Survey.

Seismicity remains low with periodic low-amplitude tremor bursts lasting 30 seconds to 30 minutes occurring this week. No plumes have been reported.

During times of northerly winds, the Anatahan plume, if present, could be directed towards the CNMI and Guam. If this happens, residents may notice hazy air conditions and smell sulfur. The Emergency Management Office (EMO) of the CNMI government will issue volcanic haze and sulfur advisories if appropriate.

Access to the island may be restricted by the CNMI government. Contact the EMO to get the latest information.

USGS contact information: duty scientist (808) 967-8815 http://volcano.wr.usgs.gov/cnmistatus.php

YELLOWSTONE VOLCANO OBSERVATORY MONTHLY UPDATE
Tuesday, September 2, 2008 13:31 MDT (Tuesday, September 2, 2008 19:31 UTC)

YELLOWSTONE VOLCANO (CAVW#1205-01-)
44.43°N 110.67°W, Summit Elevation 9203 ft (2805 m)
Volcano Alert Level: NORMAL
Aviation Color Code: GREEN

AUGUST 2008 Yellowstone Seismicity Summary

During the month of August 2008, 146 earthquakes were located in the Yellowstone region. The largest event was a magnitude 2.3 on August 31 at 7:31 AM MDT, located about 17 miles west northwest of West Yellowstone, MT. Three swarms occurred during the month of August. The first was a continuation of of a swarm that started July 28th on the Madison Plateau. The swarm continued until August 5th with an additional 52 events with magnitudes from -0.4 to 2.1, bringing the total for the swarm to 184 earthquakes. The second swarm, between Aug 3 and 7, included 28 events and was located 16 miles east northeast of West Yellowstone, MT with magnitudes 0.0 to 1.4. The third swarm on August 7 and 8 included 32 events, and was located 6 miles southeast of West Thumb. Magnitudes ranged from 0.0 to 2.1.

Earthquake activity in the Yellowstone region is at relatively low background levels.

Ground Deformation Summary: Through August 2008, continuous GPS data show that much of the Yellowstone caldera continued moving upward, though at a lower rate than the past several years. The maximum measured ground uplift over the past 48 months is ~20 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.

An article on the current uplift episode at Yellowstone and discussion of long-term ground deformation at Yellowstone and elsewhere can be found at: http://volcanoes.usgs.gov/yvo/2007/upsanddowns.html

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The Yellowstone Volcano Observatory (YVO) is a partnership of the U.S. Geological Survey (USGS), Yellowstone National Park, and University of Utah to strengthen the long-term monitoring of volcanic and earthquake unrest in the Yellowstone National Park region. Yellowstone is the site of the largest and most diverse collection of natural thermal features in the world and the first National Park. YVO is one of the five USGS Volcano Observatories that monitor volcanoes within the United States for science and public safety.