ALASKA VOLCANO OBSERVATORY WEEKLY UPDATE
U.S. Geological Survey
Friday, January 27, 2012, 2:26 PM AKST (Friday, January 27, 2012, 23:26 UTC)
WRANGELL VOLCANO
(VNUM #315020)
62°21" N 144°1'10" W,
Summit Elevation 14163 ft (4317 m)
Current Volcano Alert Level: UNASSIGNED
Current Aviation Color Code: UNASSIGNED
AVO can no longer seismically monitor Wrangell volcano because of seismic station outages. As a result, AVO is unable to assess seismic activity at this volcano. As at other volcanoes without real-time seismic networks, AVO will continue to use satellite data and reports from pilots and ground observers to detect signs of eruptive activity.
Because Wrangell is no longer seismically monitored, earlier today we changed both the Volcano Alert Level from Normal and Aviation Color Code from Green to "UNASSIGNED". Wrangell will likely remain without real-time seismic monitoring until the summer of 2012, when necessary upgrades to the network will occur.
Mt. Wrangell is a 4317 m (14,163 ft) high, andesitic, shield volcano with an ice-filled summit caldera, located in the Wrangell-St. Elias National Park and Preserve. Mt. Wrangell has three small post-caldera craters, named North Crater, East Crater, and Mt. Zanetti. These craters are all geothermally active, and there are frequent historical reports of steam from Mt. Wrangell. There are also several questionable reports of historical eruptive activity. Mt. Wrangell is 330 km (206 mi) northeast of Anchorage.
CLEVELAND VOLCANO
(VNUM #311240)
52°49'20" N 169°56'42" W,
Summit Elevation 5676 ft (1730 m)
Current Volcano Alert Level: ADVISORY
Current Aviation Color Code: YELLOW
No new activity was detected at Cleveland volcano this week. Clouds obscured views of the volcano by satellite this week.
Satellite data indicate that the lava dome that formed throughout the fall-winter of 2011 was largely removed and covered by the explosive activity of late December. It is uncertain if eruptive activity at Cleveland has ended, paused, or is occurring at a level below our detection capabilities. It remains possible for intermittent, sudden explosions of blocks and ash to occur at any time, and ash clouds exceeding 20,000 feet above sea level may develop. Such explosions and their associated ash clouds may go undetected in satellite imagery for hours. If a large, explosive, ash-producing event occurs, seismic, infrasound, or volcanic lightning may be detected by local and regional monitoring networks. There is no real-time seismic monitoring network on Mount Cleveland.
Additional information on Cleveland Volcano and the current activity may be found at this link:
http://www.avo.alaska.edu/activity/Cleveland.php
Please see http://www.avo.alaska.edu/color_codes.php for complete definitions of Aviation color codes and Volcano alert levels.
Cleveland volcano forms the western half of Chuginadak Island, a remote and uninhabited island in the east central Aleutians. It is located about 75 km (45 mi.) west of the community of Nikolski, and 1500 km (940 mi.) southwest of Anchorage. The volcano's most recent significant eruption began in February, 2001 and it produced 3 explosive events that produced ash clouds as high as 12 km (39,000 ft) above sea level. The 2001 eruption also produced a rubbly lava flow and hot avalanche that reached the sea.
OTHER ALASKA VOLCANOES
Seismic activity is monitored in real time at 29 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. Akutan, Aniakchak, Augustine, Dutton, Fisher, Fourpeaked, Gareloi, Great Sitkin, Griggs, Iliamna, Isanotski, Kanaga, Katmai, Mageik, Makushin, Martin, Novarupta, Okmok, Pavlof, Redoubt, Shishaldin, Snowy, Spurr, Tanaga, Trident, Ugashik-Peulik, Ukinrek Maars, Veniaminof, and Westdahl 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 of these volcanoes.
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:
John Power, Scientist-in-Charge, USGS
jpower@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.