Friday, August 31, 2007 1:50 PM AKDT (2150 UTC)
PAVLOF VOLCANO (CAVW#1102-03-)
55°24′57″ N161°53′24″ W, Summit Elevation 8261 ft (2518 m)
Current Aviation Color Code: ORANGE
Current Volcano Alert Level: Watch
Seismic activity remains elevated at Pavlof Volcano. Thermal anomalies and steam and weak ash plumes reaching up to 20,0000 ft (6 km) above seal level continue to be observed by satellite. Web camera views were cloudy today.
If activity continues to increase, larger ash clouds that could affect higher-flying aircraft may be produced. The most immediate ground hazard in the vicinity of the volcano includes light ash fall on nearby communities. Previous historical eruptions from Pavlof caused only a few millimeters (about 1/10th of an inch) of ash to fall on King Cove, Nelson Lagoon, Cold Bay, and Sand Point. Mudflows in drainages from the flanks of the volcano, and lava flows and avalanching of hot debris on the upper reaches of the volcano are also of concern in the uninhabited areas around the volcano. Satellite and seismic data and eyewitness observations suggest most of the surface lava activity is occurring on the southeast sector of the steep-sided volcano; this suggests that the Pacific Ocean side of the volcano is at most risk from avalanching hot debris.
At this time, we expect this eruption to follow the pattern of previous eruptions. The last eruption of Pavlof began in September 1996 and consisted of a several-month-long series of ash explosions, lava-fountaining, and lava-flow production. Ash clouds reached as high as 30,000 ft asl on one occasion. However, most ash clouds were below 20,000 ft asl. Prior to 1996, Pavlof erupted in 1986 sending ash as high as 49,000 ft asl on at least one occasion. A hazard assessment for Pavlof and the Emmons Lake volcanic center is available on the web at http://www.avo.alaska.edu/pdfs/SIR2006-5248.pdf
CLEVELAND VOLCANO (CAVW#1101-24-)
52°49′20″ N169°56′42″ W, Summit Elevation 5676 ft (1730 m)
Current Aviation Color Code: ORANGE
Current Volcano Alert Level: Watch
Satellite and web camera views were cloudy today.
AVO continues to monitor the volcano closely 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.
Cleveland volcano forms the western half of Chuginadak Island, a remote and uninhabited island in the east central Aleutians. It is located about 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 had 3 explosive events that produced ash clouds as high as 12 km (39,000 ft) above sea level. This eruption also produced a rubbly lava flow and hot avalanche that reached the sea. The most recent minor ash emissions were observed in October 2006.
KOROVIN VOLCANO (ATKA ISLAND) (CAVW#1101-16)
52°22′48″ N174°9′22″ W, Summit Elevation 5030 ft (1533 m)
Current Aviation Color Code: YELLOW
Current Volcano Alert Level: Advisory
Intermittent, low-level seismic activity continues at Korovin. Satellite views were cloudy today.
Korovin has erupted several times in the past 200 years, most recently in 1998. Eruptions typically produce minor amounts of ash and occasional, small lava flows. Ash plume heights could exceed 20,000 ft above sea level. Korovin occasionally produces large steam plumes from its summit.
Korovin Volcano is a 1553-m-high (5030 ft) stratovolcano located on the northern part of Atka Island in the central Aleutian Islands, about 184 km (110 mi) east of Adak, 538 km (350 mi) west of Dutch Harbor, and 1760 km (1100 mi) southwest of Anchorage. The volcano has two distinct summit vents about 0.6 km (2000 ft) apart, that have been the sites of eruptive activity as recently as June, 1998. The most recently active of the vents maintains a small, roiling, lake that occasionally produces energetic steam emissions. Thermal springs and fumaroles located on and near the volcano indicate an active hydrothermal system. Korovin has erupted several times in the past 200 years, including 1907, 1951, 1953, 1954, 1973, 1976, 1986, 1987, 1996, and 1998. All of these eruptions produced minor amounts of ash and occasional but small lava flows. Reports of the height of the ash plume produced by the 1998 eruption ranged from 4900 to 9200 m (16,000 to 30,000 feet) above sea level.
