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Alaska Volcano Observatory

Alaska Volcano ObservatoryWeekly UpdateFriday, November 7, 2008 11:55 AM AKST (20:55 UTC)

REDOUBT VOLCANO (CAVW #1103-03-)
60°29'7" N 152°44'38" W, Summit Elevation 10197 ft (3108 m)
Current Aviation Color Code: YELLOW
Current Volcano Alert Level: ADVISORY

On Wednesday, November 5, 2008, AVO raised the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY owing to the several month long detection of potentially significant changes in gas emission and heat output from Redoubt Volcano. These changes are a departure from long-observed background activity. The remainder of the week seismic activity remained at low levels and satellite views of the volcano were partly cloudy with no activity observed. AVO staff began work to install additional geophysical equipment and a web camera on the volcano.

Heavily ice-mantled Redoubt volcano is located on the western side of Cook Inlet, 170 km (106 mi) southwest of Anchorage and 82 km (51 mi) west of Kenai, within Lake Clark National Park. Redoubt is a stratovolcano which rises to 10,198 feet above sea level. Recent eruptions occurred in 1902, 1966-68, and 1989-90. The 1989-90 eruption produced mudflows, or lahars, that traveled down the Drift River and partially flooded the Drift River Oil Terminal facility. The ash plume produced by the 1989-90 eruption affected international air traffic and resulted in minor or trace amounts of ash in the city of Anchorage and other nearby communities.

OKMOK VOLCANO (CAVW #1101-29-)
53°23'49" N 168°9'58" W, Summit Elevation 3520 ft (1073 m)
Current Aviation Color Code: YELLOW
Current Volcano Alert Level: ADVISORY

Seismic activity at Okmok Volcano remained low all week with a few possible tremor bursts over the last 24-hour period. Throughout the week satellite views of the volcano were mostly cloudy with no activity observed.

Although the level of seismicity is relatively low, it is possible, but growing increasingly unlikely, that vigorous ash emissions will resume.

Okmok volcano is a 6-mile-wide caldera that occupies most of the eastern end of Umnak Island, located 75 miles southwest of Dutch Harbor in the eastern Aleutian Islands. Okmok has had several eruptions in historic time typically consisting of ash emissions occasionally to over 30,000 feet ASL but generally much lower; lava flows crossed the caldera floor in 1945, 1958, and 1997.

The nearest settlement is Nikolski, population about 35, roughly 45 miles west of the volcano. A ranch caretaker family lives at Fort Glenn on the flank of the volcano about 6 miles east of the caldera rim.


OTHER ALASKA VOLCANOES

Seismic activity is monitored in real time at 31 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, 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, November 7, 2008 08:16 PST (Friday, November 7, 2008 16:16 UTC)

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

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 volcano, Mount Shasta, and Lassen Peak in northern California.
Mount St. Helens has been at Volcano Alert Level NORMAL (Aviation Color Code GREEN) since July 10, 2008, a change assigned 5-6 months after the late January cessation of its 2004-2008 eruption.

Volcano seismicity in the Cascades has remained quiet over the past week. Given the onset of wet weather, and snow at higher elevations, this has also been a quiet week for field work in the Cascades.

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
Friday, November 7, 2008 07:58 HST (Friday, November 7, 2008 17:58 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 961-8093.

Activity Summary for last 24 hours: No significant changes have occurred. Sulfur dioxide emission rates from the Halema`uma`u and the Pu`u `O`o vents remain high. Tephra production from the Halema`uma`u vent remains small. At the east rift eruption site, lava flows through tubes to the ocean; surface flows are active on the pali.

Last 24 hours at Kilauea summit: Moderate to strong trade winds kept the plume low over the Ka`u Desert except for a few hours around noon when weakened winds allowed the plume to rise vertically. Vent glow was sometimes visible but too weak to be recorded by the webcam overnight. This morning, the light brown gas plume arcs up and over the crater rim and is moving southwestward over the Ka`u Desert. GOES-WEST imagery shows the plume moving southwestward well inland of the coast.

Sulfur dioxide emission rates remain elevated and variable. The most recent average measurement was 700 tonnes/day on November 3, compared to the 2003-2007 average rate of 140 tonnes/day.

Variable but small amounts of tephra, mostly ash-sized spatter, continue to be produced and deposited downwind of the vent; this morning's collection was on the large side but may contain some ground debris blown in by yesterday's strong winds. The vent was louder this morning with distant surf and some rock fall sounds.

The network of tiltmeters within Kilauea caldera again recorded no coherent tilting. The GPS receiver networks (less sensitive than tiltmeters) recorded weak contraction (barely 1 cm per month).

Seismic activity continued at low levels focused on the south caldera; tremor levels almost doubled after 10:15 pm. A total of 11 earthquakes were located beneath Kilauea or nearby, including 4 beneath the south caldera and 4 on south flank faults, with the number of RB2S2BL earthquakes at background values around 40/day.

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 November 3 is at the 2003-2007 average of about 1,700 tonnes/day for this vent; this is the first Pu`u `O`o emission rate in the average range since early September. No incandescence was observed within the crater overnight.

The tiltmeter on the north side of Pu`u `O`o recorded weak deflation. GPS stations spanning the crater (less sensitive than tiltmeters) recorded about 4 cm of contraction over the past 3 months. Seismic tremor levels near Pu`u `O`o and the TEB vent remain at low values.

Lava from the TEB vent and the rootless shield complex flows through tubes to the ocean. HVO geologists yesterday mapped flows within the abandoned Royal Gardens subdivision which resulted in some flows extending 1.2 km from the base of that pali south onto the coastal plain (see map); the Waikupanaha ocean entry was strong at the time of their reconnaissance and revealed evidence of a small bench collapse sometime Wednesday night/Thursday morning. Weak incandescence was seen overnight from the TEB vent area. GOES-WEST imagery showed a persistent thermal anomaly overnight suggesting continuing surface flow activity. CD officials this morning report a large plume from the ocean entry.

Definitions of terms used in the update:

FLIR: Forward Looking InfraRed, a camera which directly images heat rather than visible light. If volcanic fume is not too rich in water vapor, a FLIR can see through it to image hot surfaces.

pali: Hawaiian word for cliff or steep incline. In the context of the TEB flow field, 'pali' usually refers to Pulama pali that bisects the abandoned Royal Gardens subdivision.

CD: Hawai`i County Civil Defense

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
Friday, November 7, 2008 09:41 PST (Friday, November 7, 2008 17:41 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

There were no earthquakes large enough to be located by the real-time detection system in the Long Valley area since the last update at 10:36 AM on Thursday, November 6.

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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.

Report prepared by the U.S. Geological Survey.

Short bursts of low-level tremor were observed this week and small bursts of long period earthquakes were observed on Tuesday, November 4 (Saipan time). However, overall seismicity has remained low. Nothing unusual was observed in satellite images obtained throughout the week. No reports of eruptive activity or other unusual volcanic phenomena at Anatahan were received this week.
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.

YELLOWSTONE VOLCANO OBSERVATORY MONTHLY UPDATE
Saturday, November 1, 2008 16:50 MDT (Saturday, November 1, 2008 22:50 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

OCTOBER 2008 Yellowstone Seismicity Summary

During the month of October 2008, 46 earthquakes were located in the Yellowstone region. The largest event was a magnitude 2.4 on October 5 at 3:12 PM MDT, located about 13 miles northeast of West Yellowstone, MT. No swarms were recorded during October.

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

Ground Deformation Summary: Through October 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 50 months is ~21 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.