Last Wednesday, AVO assigned Fourpeaked a level of concern of yellow in its four-color system, defined as elevated seismic activity with the potential of an eruption. Fourpeaked previously was not assigned a level of concern.

In an update Monday, AVO warned that an eruption in the next days to week is possible. The update listed three scenarios, with the most likely first:

n A small to moderate eruption, with ash plumes higher than 33,000 feet and possible lava flows;

n No eruption, with the current unrest subsiding to background levels;

n A large eruption, with ash plumes higher than 33,000 feet and a widespread ash fall.

Since last Wednesday, scientists have flown over Fourpeaked, done chemical analyses and temperature readings of gas coming off the west flank and installed seismometers about 7 miles to the east of the mountain. West said AVO crews will be installing other instruments in the next few weeks. GPS instruments have not yet been put in, so it’s not known if there has been deformation or swelling of Fourpeaked, as happened with Augustine Volcano before it erupted in mid-January.

Fourpeaked is acting like Augustine in other ways, West said. On a flight Sunday, scientists photographed a line of fumaroles, or volcanic vents, steaming through a glacier along the west flank of Fourpeaked. West said some ash was seen around some of the vents. Measurements at the vents showed temperatures of 140 degrees Fahrenheit, and the presence of sulfur dioxide, hydrogen sulfide and carbon dioxide, all in high amounts. Ash samples were taken, but have not yet been fully analyzed.

A “rotten egg” sulfur smell was also noticed up to 30 miles away. Sulfur dioxide was present in amounts similar to that measured on Augustine in late December and early January before it erupted on Jan. 11.

“That’s the one we use the most. It’s a fairly robust measurement — it’s one we have experience interpreting,” West said.

Scientists also noticed flooding and disturbance of glaciers near the summit.

“Whatever is going on is going on beneath a layer of snow and ice, and has managed to break through a few areas with steam,” West said.

Although the Fourpeaked Volcano page on AVO’s site has a webicorder — a graph of daily seismometer activity near the mountain — West noted that the station, CDD, is 7 miles away, further than webicorders on Augustine, which are within a mile of the peak. Measurements shouldn’t be interpreted the same as with Augustine. Station CDD also is measuring activity on nearby volcanoes.

If Fourpeaked erupts, the most likely hazard would be from airborne ash.

“The kinds of ash hazards would not be unlike the ash hazards from Augustine,” West said.

Homer and other Kachemak Bay area communities had a slight dusting of ash during the eruptions in mid-January. Scientists have been studying satellite and radar images of Fourpeaked, and are developing models to see how far and where ash could spread if it erupted. There also is a danger on the mountain from floods or debris and volcanic mud flows.

Fourpeaked lacks not only the heavy instrumentation of Augustine before it erupted, but also its history.

“Augustine has a long historic record of what we might expect. There is no typical behavior for Fourpeaked in the modern era,” West said.

Scientists haven’t gone to 24-7 hours yet, but they are checking seismographs four times a day, West said.

“Everyone is dialed in on this — our colleagues at USGS and DGGS,” he said.

For more information and the latest updates, visit the AVO Web site at www.avo.alaska.edu, or call a recording at (907) 786-7478. Information on emergency preparedness is available at the AVO Web site or at the Kenai Peninsula Borough’s Office of Emergency Management Web site at www.borough.kenai.ak.us/emergency/-prepared/volcano.htm.

The National Weather Service produces ash trajectory forecasts for Augustine and Fourpeaked volcanoes on its Web site at www.arl.noaa.gov/ready/traj_alaska.html.

A December 2005 article in the Homer News, “Get out the panty hose: What to do if Augustine blows,” also offers advice for preparing for volcano dangers. A link to that article is on the main Homer News Web page at www.homernews.com.