Alaska Volcano Is Poised to Erupt

One of Alaska's most active volcanoes could be working toward a massive eruption that could affect air travel but was not expected to threaten any of the towns in the area, scientists said Thursday.

Satellite images of Pavlof Volcano taken Thursday showed strong thermal readings, consistent with what the Alaska Volcano Observatory is calling a "vigorous eruption of lava" at the volcano about 590 miles southwest of Anchorage on the Alaska Peninsula.

The volcano is below the path of hundreds of daily international flight paths, and an explosive eruption could interrupt those operations, said Steve McNutt, a volcano seismologist with the observatory. Volcanic ash can enter an engine and make it seize up, he said.

The Federal Aviation Administration sent advisories to airlines that might be operating in the area and is monitoring the situation, said spokesman Allen Kenitzer. If there is a severe eruption, flights would have to be diverted, possibly resulting in delays, he said.

McNutt said seismic activity is high at the 8,262-foot volcano, with about one tremor recorded every minute. Lahars mudslides caused when lava melts snow on the peak have triggered some seismic activity, as well, he said.

The mudslides took place on the southeast side of the volcano, an area he said is inhabited by few, if any, people. Pavlof is about nine miles from Pavlof Bay, a popular fishing ground, but at the moment it isn't posing an immediate threat, McNutt said.

He said hazards the volcano could present included light ash fall on nearby communities, mud flows, lava flows and hot debris avalanching on the volcano's flanks.

Several small towns are in the area, including King Cove, which is about 35 miles to the southwest with a population of roughly 800, and Cold Bay, nearly 40 miles southwest with a population of about 90. But they're too far to be affected by lava, and McNutt said an eruption probably would coat the towns with no more than a 2- or 3-millimeter-thick blanket of ash.

Josh Gould, co-owner of King Cove grocer John Gould & Sons Co. Inc., said people in town were preparing for the worst while hoping for the best. Sales of basic staples are up, he said, but there's no danger of running out of products like water, bread and milk.

He said that an ash plume was visible from town, but that none was falling on it yet.

Seismic activity was first picked up at the volcano Tuesday. Eyewitnesses aboard a fishing boat in the area Wednesday reported glowing lava on the volcano's southeast flank. Pilots have reported a weak plume of ash drifting 5 miles to the southwest and likely below 20,000 feet.

"What we think we're in for is several months of low-level eruptions punctuated by a few large and explosive events," McNutt said.

Pavlof, which has had about 40 eruptions since record keeping began in the area in the 1760s, is among the most closely monitored volcanoes in the state, with permanent monitoring equipment installed nearby.

Its last eruption was in 1996; that 11-year span is the longest Pavlof has gone without an event, McNutt said. A string of eruptions took place during the 1970s and 1980s.

A series of ash explosions and lava eruptions took place for several months after the last eruption. Ash clouds reached as high as 30,000 feet at the time. During a 1986 eruption, Pavlof spewed ash as high as 49,000 feet.

The intensity of earthquake activity at Pavlof Volcano has continued to slowly increase from yesterday. Strong signals at a single station southeast of the summit suggest flow events, probably lahars (or mudflows), on that flank. Satellite images of the volcano overnight and this morning continue to show a strong thermal feature at Pavlof. Residents of both Cold Bay and Sand Point observed last night incandescence at the summit.

These observations are consistent with vigorous eruption of lava at the surface; explosions producing ash do not seem to be significant at this time and any ash produced is likely staying below 15 - 20,000 ft above sea level. AVO is maintaining aviation color code ORANGE and volcanic activity alert level WATCH at this time.

The primary hazard from this eruption is airborne ash. If activity continues to increase in intensity, larger ash clouds that could affect 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, 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 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

AVO continues to monitor the activity closely; satellite and seismic data are checked frequently around the clock. We are investigating the installation of additional monitoring equipment including a web camera.

Pavlof volcano is a steep-sided, symmetrical, 8261-ft-high stratovolcano located on the southwestern end of the Alaska Peninsula about 590 miles southwest of Anchorage. The community of Cold Bay is located 37 miles to the southwest of Pavlof; Nelson Lagoon, King Cove, and Sand Point are other communities within 75 miles of the volcano. With almost 40 historic eruptions, it is one of the most active volcanoes in the Aleutian arc. Eruptive activity is generally characterized by sporadic lava fountaining continuing for a several-month period. Additional hazards in the vicinity of the volcano included light ash fall on nearby communities, mudflows, lava flows and avalanching of hot debris on the flanks of the volcano. For more information on Pavlof and potential volcano hazards, please see our web site: http://www.avo.alaska.edu/volcanoes/volcinfo.php?volcname=Pavlof

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