ALASKA VOLCANO OBSERVATORY WEEKLY UPDATE
U.S. Geological Survey
Friday, January 10, 2014, 1:34 PM AKST (Friday, January 10, 2014, 22:34 UTC)
56°11'52" N 159°23'35" W,
Summit Elevation 8225 ft (2507 m)
Current Volcano Alert Level: ADVISORY
Current Aviation Color Code: YELLOW
Seismicity at Veniaminof has remained slightly above background over the past week. Nothing has been observed in webcam or satellite images over the past week and AVO has received no reports of unrest from local observers.
Although the last observation of minor ash emission was in October, lava effusion and ash emission could resume at any time. Pauses in eruptive activity of weeks to months are not uncommon at Veniaminof.
Mount Veniaminof volcano is an andesitic stratovolcano with an ice-filled 10-km diameter summit caldera located on the Alaska Peninsula, 775 km (480 mi) southwest of Anchorage and 35 km (22 mi) north of Perryville. Veniaminof is one of the largest (~ 300 cubic km) and most active volcanic centers in the Aleutian Arc and has erupted at least 13 times in the past 200 years. Recent significant eruptions of the volcano occurred in 1993-95 and 2005. Both were Strombolian eruptions producing lava fountans and minor emissions of ash and gas from the main intracaldera cone. During the 1993-95 activity, a small lava flow was extruded into the ice field producing a melt pit. Minor ash-producing explosions occurred nearly annually between 2002 and 2008. Previous historical eruptions have produced ash plumes that reached 6,000 m (20,000 ft) above sea level (1939 and 1956) and ash fallout that blanketed areas within about 40 km (25 mi) of the volcano (1939).
52°49'20" N 169°56'42" W,
Summit Elevation 5676 ft (1730 m)
Current Volcano Alert Level: WATCH
Current Aviation Color Code: ORANGE
No activity was observed over the past week in satellite views and no explosions have been detected by infrasound since January 2. Thus earlier today AVO lowered the Level of Concern Code to YELLOW and the Alert Level to Advisory.
Since mid-2011, Cleveland has produced approximately 30 small explosions and several intervals of lava effusion leading to lava domes or short lava flows. Although the volcano has been quiet for the past several days, it remains possible for brief, sudden explosions of blocks and ash from the summit vent to occur with little to no warning. These explosions may produce drifting ash clouds and local fallout of ash over the surrounding ocean, on the flanks of Cleveland Volcano, and on parts of Chuginadak Island. It is possible that more energetic explosions will occur that may produce more significant ash clouds.
If a large ash-producing event occurs, nearby seismic, infrasound, or volcanic lightning networks should alert AVO staff quickly. However, for some events, a delay of several hours or more is possible. Cleveland volcano does not have a local seismic network and is monitored using only distant seismic and infrasound instruments and satellite data.
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 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, 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
John Power, Scientist-in-Charge, USGS
firstname.lastname@example.org (907) 786-7497
Janet Schaefer, Acting Coordinating Scientist, UAFGI
email@example.com (907) 322-4085
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.