Printer friendly versionALASKA VOLCANO OBSERVATORY
Friday, January 6, 2006 12:00 PM AKST (2100 UTC)
59.3633°N 153.4333°W, Summit Elevation 4134 ft (1260 m)
Current Level of Concern Color Code: YELLOW
Unrest continues at Augustine Volcano. Seismicity rates increased slightly this week compared to last week. The last few days of this week offered clear views of the volcano and summit area in field observers photos, and in web cam and satellite images. The volcano continues to steam vigorously from several summit fumaroles. Steam and gas emissions are expected to continue and small steam explosions could occur at any time. There are no indications at this time that a large eruption is imminent. Augustine remains in color code YELLOW and AVO continues to monitor the situation closely.
The first good weather in many days also allowed AVO scientists to visit the volcano to install additional seismic monitoring equipment and deploy additional ash collection devices this week. An AVO crew also conducted thermal surveys of the summit area on Wednesday using a helicopter mounted instrument. The high-temperature fumarole or gas vent high on the south flank of the volcano, previously reported on December 22, 2005, has cooled down significantly. However, AVO did detect higher temperatures at one summit fumarole imaged through the steam and gas. While fumarole temperatures have varied, there was no significant changes in the distribution of thermal features compared to the previous survey . A gas-measurement flight, also conducted on Wednesday, detected a significant increase in sulfur-dioxide compared to the December 20 flight.
The latest observations continue to suggest that new magma is present beneath Augustine Volcano. Based on past eruptions at Augustine, AVO expects to see a sharp increase in earthquake activity prior to a significant explosive eruption. At this time, the level of seismicity is still well below that observed just prior to the 1986 eruption. However, small steam explosions are likely to continue to occur with no warning and could affect low-flying aircraft in the vicinity of the volcano.
Over the next few days, AVO will continue to conduct overflights and field visits to the island as weather permits.
Augustine Volcano is a 1260 m high (4134 ft) conical-shaped island stratovolcano located in southern Cook Inlet, about 290 km (180 mi) southwest of Anchorage, Alaska and 120 km (75 mi) southwest of Homer, Alaska. Historically, Augustine is the most active volcano in the Cook Inlet region with significant eruptions in 1812, 1883, 1908, 1935, 1963-64, 1976, and 1986. These eruptions were primarily explosive events that produced volcanic ash clouds (to 30,000-40,000 feet above sea level), ash fall, pyroclasic flows, and and lava domes or flows. During the 1883 eruption, a large avalanche on the north flank of the volcano flowed into Cook Inlet and may have initiated a tsunami observed at Nanwalek, about 90 km to the east.
61.2994°N 152.2511°W, Summit Elevation 11070 ft (3374 m)
Current Level of Concern Color Code: YELLOW
The level of seismic activity at Mount Spurr volcano remains above background. Clear satellite and web camera views of the volcano over the week showed nothing unusual. There are no indications that an eruption is imminent.
Mount Spurr volcano is an ice- and snow-covered stratovolcano located on the west side of Cook Inlet approximately 120 km (75 mi) west of Anchorage. The only known historical eruptions occurred in 1953 and 1992 from the Crater Peak flank vent located 3.5 km (2 mi) south of the summit of Mount Spurr. These eruptions were brief, explosive, and produced columns of ash that rose up to 20 km (65,000 ft) above sea level and deposited several mm of ash in south-central Alaska, including approximately 6 mm of ash on Anchorage in 1953. The last known eruption from the summit of Mount Spurr was more than 5,000 years ago. Primary hazards during future eruptions include far-traveled ash clouds, ash fall, pyroclastic flows, and lahars or mudflows that could inundate drainages all sides of the volcano, but primarily on the south and east flanks.
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. Wrangell, Redoubt, Iliamna, Snowy, Griggs, Katmai, Novarupta, Trident, Mageik, Martin, Peulik, Ukinrek Maars, Aniakchak, Veniaminof, Pavlof, Dutton, Isanotski, Shishaldin, Fisher, Westdahl, Akutan, Makushin, Okmok, Korovin, Great Sitkin, Kanaga, Tanaga, and Gareloi volcanoes are in color code GREEN. 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.
ABBREVIATED COLOR CODE KEY
(contact AVO for complete description):
GREEN volcano is dormant; normal seismicity and fumarolic activity occurring
YELLOW volcano is restless; eruption may occur
ORANGE volcano is in eruption or eruption may occur at any time
RED significant eruption is occurring or explosive eruption expected at any time
VOLCANO INFORMATION ON THE INTERNET: http://www.avo.alaska.edu
RECORDING ON THE STATUS OF ALASKA'S VOLCANOES (907) 786-7478
Tom Murray, Scientist-in-Charge, USGS
firstname.lastname@example.org (907) 786-7497
Jon Dehn, Acting Coordinating Scientist, UAF-GI
email@example.com (907) 474-6499
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.