Alaska Volcano Observatory
Current Status Report
Tuesday, July 15, 2008 11:49 AM AKDT (19:49 UTC)
OKMOK VOLCANO (CAVW #1101-29-)
53°23’49” N 168°9’58” W, Summit Elevation 3520 ft (1073 m)
Current Aviation Color Code: RED
Current Volcano Alert Level: WARNING
Okmok Volcano continues to erupt. Seismicity, though below this weekend’s intensity, has remained steady over the last 24 hours. Satellite data continue to show a long (~250 km) plume moving east; the height of the plume is approximately 30,000 ft above sea level.
The volcano is currently at aviation color code RED and alert level WARNING. All areas immediately around the volcano are considered hazardous. Airborne ash and gas continues to drift with the wind and pose a hazard to aviation in the area. Additional ash fall will occur on Umnak Island and possibly adjacent islands as long as the eruption continues.
OMI image showing the extent of the sulfur dioxide gas cloud from the eruption of Okmok Volcano. The large red mass is from the main explosive phase on 12 July at 21:30 UTC and is at an estimated height of 50,000 ft above sea level. The north-south dimension of this cloud is about 850 miles. Current emissions from the volcano are at a lower altitude of approximately 30,000 to 35,000 feet. Other OMI data (not shown) indicate that volcanic ash is mixed with the sulfur dioxide cloud. Picture Date: July 14, 2008 UTC – Image Creator: Dave Schneider – Data provided through the OMI near-real-time decision support project funded by NASA.
CLEVELAND VOLCANO (CAVW #1101-24-)
52°49’20” N 169°56’42” W, Summit Elevation 5676 ft (1730 m)
Current Aviation Color Code: YELLOW
Current Volcano Alert Level: ADVISORY
Satellite and webcam views continue to be cloudy today. AVO has received no reports of eruptive activity at the volcano.
AVO monitors Cleveland Volcano with satellite imagery as weather allows. The lack of a real-time seismic network at Cleveland means that AVO is unable to track local earthquake activity related to volcanic unrest. Short-lived explosions of ash that could exceed 20,000 ft above sea level can occur without warning and may go undetected on satellite imagery. Please see http://www.avo.alaska.edu/activity/Cleveland.php for more information.
Astronaut photograph of May 23, 2006 eruption of Cleveland Volcano. Image Science and Analysis Laboratory, NASA-Johnson Space Center. Original NASA Caption:
At 3:00 p.m. Alaska Daylight Time on May 23, 2006, Flight Engineer Jeff Williams from International Space Station (ISS) Expedition 13 contacted the Alaska Volcano Observatory (AVO) to report that the Cleveland Volcano had produced a plume of ash. Shortly after the activity began, he took this photograph. This picture shows the ash plume moving west-southwest from the volcano’s summit. A bank of fog (upper right) is a common feature around the Aleutian Islands. The event proved to be short-lived; two hours later, the plume had completely detached from the volcano (see image from May 24). The AVO reported that the ash cloud height could have been as high as 6,000 meters (20,000 feet) above sea level.
Cleveland Volcano, situated on the western half of Chuginadak Island, is one of the most active of the volcanoes in the Aleutian Islands, which extend west-southwest from the Alaska mainland. It is a stratovolcano, composed of alternating layers of hardened lava, compacted volcanic ash, and volcanic rocks. At a summit elevation of 1,730 meters, this volcano is the highest in the Islands of the Four Mountains group. Carlisle Island to the north-northwest, another stratovolcano, is also part of this group. Magma that feeds eruptions of ash and lava from the Cleveland Volcano is generated by the northwestward movement of the Pacific Plate beneath the North American Plate. As one tectonic plate moves beneath another—a process called subduction—melting of materials above and within the lower plate produces magma that can eventually move to the surface and erupt through a vent (such as a volcano). Cleveland Volcano claimed the only known eruption-related fatality in the Aleutian Islands, in 1944.
Small explosion at Cleveland volcano on July 20, 2007. This photo, taken from the USFWS research vessel Norseman, shows a small ash cloud rising a few thousand feet above the summit and drifting downwind. This type of intermittent explosive activity is likely characteristic of the current level of unrest at Cleveland. Such small ash clouds can easily go undetected on satellite imagery. Image taken from FWV Tiglax, from NE of Cleveland looking SW. Tana is to the left in the image, Kagamil and Carlisle off the image to the right. Dissipating plume from a small eruptive burst, likely Strombolian, from the summit of Cleveland volcano. Picture Date: July 20, 2007 – Image Creator: Doug Dasher – Image Creator: Max Hoberg – Photo courtesy of School of Fisheries, UAF.
Image of Herbert (left-most volcano), Carlisle (upper volcano) and Mount Cleveland (stratovolcano with small steam plume). Mission: ISS001 Roll: E Frame: 5962 Mission ID on the Film or image: ISS01 Country or Geographic Name: USA-ALASKA Features: ISLANDS OF FOUR MTS.,SMK Center Point Latitude: 53.0 Center Point Longitude: -170.0 – Picture Date: January 01, 2001 00:11:15 GMT – Image courtesy of the Image Analysis Laboratory, NASA Johnson Space Center.
Location of Cleveland volcano and other Aleutian volcanoes with respect to nearby cities and towns.
Picture Date: February 06, 2006 – Image Creator: Janet Schaefer – Image courtesy of the AVO/ADGGS.
John Power, Acting Scientist-in-Charge, USGS
Steve McNutt, Coordinating Scientist, UAFGI
Volcano Alert Levels
Volcano is in typical background, noneruptive state or, after a change from a higher level, volcanic activity has ceased and volcano has returned to noneruptive background state.
Volcano is exhibiting signs of elevated unrest above known background level or, after a change from a higher level, volcanic activity has decreased significantly but continues to be closely monitored for possible renewed increase.
Volcano is exhibiting heightened or escalating unrest with increased potential of eruption, timeframe uncertain, OR eruption is underway but poses limited hazards.
Hazardous eruption is imminent, underway, or suspected.