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Alaska Volcano Observatory

ALASKA VOLCANO OBSERVATORY WEEKLY UPDATEFriday, November 6, 2009 12:31 PM (Friday, November 6, 2009 21:31 UTC)

ANATAHAN VOLCANO (CAVW #0804-20=)
16°21' N 145°40'12" E, Summit Elevation 2592 ft (790 m)
Current Aviation Color Code: GREEN
Current Volcano Alert Level: NORMAL

Report prepared by the U.S. Geological Survey.

No reports of eruptive activity at Anatahan were received the past week, and seismic levels have remained low. Nothing unusual was observed in satellite images throughout the 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.

CONTACT INFORMATION:
USGS Northern Marianas Duty Scientist (808) 967-8815
http://volcano.wr.usgs.gov/cnmistatus.php

CNMI Emergency Management Office (670) 322-8001
http://www.cnmiemo.gov.mp/

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.

Recent Observations: Data from monitoring equipment have indicated only background levels of activity at Cascade Range volcanoes during the week. A series of strong Pacific storms has pounded the Cascades Range this week, however, sometimes producing noisy seismometer outputs unrelated to volcanic or tectonic activity. No earthquakes have been recorded at Lassen Peak volcano since abatement of the November 2-16 swarm.

HAWAIIAN VOLCANO OBSERVATORY DAILY UPDATESaturday, November 21, 2009 08:16 AM (Saturday, November 21, 2009 18:16 UTC)

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.

KILAUEA VOLCANO (CAVW #1302-01-)
19°25'16" N 155°17'13" W, Summit Elevation 4091 ft (1247 m)
Current Aviation Color Code: ORANGE
Current Volcano Alert Level: WATCH

Activity Summary for past 24 hours: A DI event is nearly complete. At the summit, a circulating, bubbling, and spattering lava pond surface was visible in a hole in the vent cavity floor deep beneath Halema`uma`u Crater floor; its level rose several meters covering the entire vent floor before dropping but remaining visible in the Overlook vent Webcam. Sulfur dioxide emission rates from the Halema`uma`u and east rift zone vents remain elevated. Lava flows are active on the coastal plain; lava flows through tubes to the coast and is entering the ocean at two locations west of Kalapana.

Past 24 hours at Kilauea summit: The lava pond continued bubbling and circulating at its low level within a hole in the vent cavity floor deep beneath the vent rim (in the Halema`uma`u Crater floor) until 7:23 pm when it abruptly rose several meters, peaking and covering the entire vent floor at about 7:30 pm, then draining back into the hole nearly an hour later; the lava level in the hole remained higher than it was when the night started but lower than the 7:30 pm peak. Glow is visible from the Jaggar Museum Overlook. This morning, the dense white plume moves to the southwest through beautiful clear skies. The most recent sulfur dioxide emission rate measurement was 800 tonnes/day on November 20, still elevated above the 2003-2007 average of 140 tonnes/day. Very small amounts of mostly ash-sized tephra continued to drop out of the plume near the vent.

The summit tiltmeter network recorded weak inflation completing the most recent DI event. The GPS network, which is less sensitive than the tiltmeter network, recorded contraction starting at the beginning of November switching to extension after November 12th.

Seismic tremor levels remained at low values with a drop. The number of RB2S2BL earthquakes remained below background levels. Two earthquakes were strong enough to be located on south flank faults.

Past 24 hours at the middle east rift zone vents and flow field: Magma continued to degas through Pu`u `O`o crater before erupting from the TEB vent, located 2 km to the east. The most recent sulfur dioxide emission rate measurement was 1,300 tonnes/day on November 21, below the 2003-2007 average of 1,700 tonnes/day. Very weak glow was again recorded from the crater last night.

The tiltmeter on the north flank of Pu`u `O`o recorded the switch to DI inflation around 9:30 an yesterday and continued slow inflation. The GPS network, which is less sensitive than the tiltmeter network, recorded continued slow contraction of the cone, amounting to almost 3 cm of contraction over the past 3 months. Seismic tremor levels at Pu`u `O`o and the TEB vent were at low values.

Lava flows through two tube branches to the coast, across State- and privately-owned land, and was entering the ocean at two general locations - Waikupanaha and west Waikupanaha 700 m (2,300 ft) to the west. Yesterday, HVO geologists found scattered surface flows over the coastal plain and at least one possible surface flow on the pali; a single entry at Waikupanaha and several at the west Waikupanaha location were active. GOES-WEST imagery showed thermal anomalies on the coastal plain suggesting continuing surface flow activity through dawn.

HAZARD ALERT: The lava delta and adjacent areas both inland and out to sea are some of the most hazardous areas on the flow field. Frequent delta/bench collapses give little warning, can produce hot rock falls inland and in the adjacent ocean, and can produce large local waves. The steam plume produced by lava entering the ocean contains fine lava fragments and an assortment of acid droplets that can be harmful to your health. The rapidly changing conditions near the ocean entry have been responsible for many injuries and a few deaths.

Maps, photos, webcam views, and other information about Kilauea Volcano are available at http://volcanoes.usgs.gov/hvo/activity/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/activity/alertsystem/index.php

Definitions of Terms Used:

glow: light from an unseen source; indirect light.

CD: Hawai`i County Civil Defense

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

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

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.

More definitions with photos can be found at http://volcano.wr.usgs.gov/about/pglossary/index.php .

The Hawaiian Volcano Observatory is one of five volcano observatories within the U.S. Geological Survey and is responsible for monitoring volcanoes and earthquakes in Hawai`i.

The real-time computer system located just one small earthquake in the vicinity of Long Valley caldera since the last update at 9:26 AM (PST) on November 20. This was a magnitude M=1.6 earthquake at 3:51 PM on the 20th centered at the depth of 5 miles beneath the eastern outskirts of Mammoth Lakes (1/4 mile north of the corrals).

NORTHERN MARIANA ISLANDS WEEKLY UPDATEFriday, November 20, 2009 10:01 AM (Friday, November 20, 2009 00:01 UTC)

ANATAHAN VOLCANO (CAVW #0804-20=)
16°21' N 145°40'12" E, Summit Elevation 2592 ft (790 m)
Current Aviation Color Code: GREEN
Current Volcano Alert Level: NORMAL

Report prepared by the U.S. Geological Survey.

No reports of eruptive activity at Anatahan were received the past week, and seismic levels have remained low. Nothing unusual was observed in satellite images throughout the 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.

CONTACT INFORMATION:
USGS Northern Marianas Duty Scientist (808) 967-8815
http://volcano.wr.usgs.gov/cnmistatus.php

CNMI Emergency Management Office (670) 322-8001
http://www.cnmiemo.gov.mp/

October 2009 Yellowstone Seismicity Summary

During the month of October 2009, 218 earthquakes were located in the Yellowstone National Park region. The largest event was a magnitude 2.5 on October 15 at 3:39 PM MDT, located about 7 miles south southeast of West Thumb, Yellowstone NP. This event was the largest event in a swarm of 138 earthquakes that occurred October 12-23, with magnitudes ranging from -0.2 to 2.5.

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

Ground Deformation Summary: Continuous GPS data show that uplift of the Yellowstone Caldera has stopped for now. The WLWY station, located in the northeastern part of the caldera, underwent a total of ~23 cm of uplift between mid-2004 and mid-2009. Its record can be found at:
http://pboweb.unavco.org/shared/scripts/stations/?checkkey=WLWY&sec=timeseries_plots×eries=raw

The general uplift and subsidence of the Yellowstone caldera is of scientific importance and will continue to be monitored closely by YVO staff.

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