Description: From McGimsey and others (2007): "In late July 2005, AVO was contacted by Vern Byrd of U.S. Fish and Wildlife Service (USFWS)/Homer who passed along a report from a USFWS field camp on Kasatochi Island, located about 50 km (~30 mi) east of Great Sitkin and about 100 km (~60 mi) west of Korovin Volcano. On June 23, members of the field party viewed the lake and noticed nothing unusual. Then, on July 27, the same field party peered into the summit crater from the rim and saw the lake 'simmering, not quite a roiling boil, concentrated in a few patchy areas, bubbling more violently in the western half of the lake, * * * lake appeared thin (sic), no steam observed at all.' The bubbling areas were intermittent. The observers did not feel vibrations or earthquakes or hear anything odd, nore did they detect unusual odors or water discoloration (the lake typically is turbid and turquoise in color). Gulls landed unperturbed on the water surface. The observers concluded that what they were seeing was a distinct change from the previous month and from conditions present during the past several years on the island.
"Biologists visited the crater rim again on August 1 and reported no significant change from the activity reported on July 27. They mentioned that the lake was perhaps 'simmering a little less with less area of the lake affected.' A check of satellite imagery for any sign of thermal anomaly or other change during this time period came up negative, however, clear views of this frequently cloud-covered small island were few (ASTER, Landsat, R. Wessels, USGS/AVO, oral commun., 2005).
"A USGS-contracted helicopter in Adak transported an AVO geologist and the USFWS field party chief Brie Drummond to Kasatochi on September 2 to investigate. Winds were high and fog and clouds intermittently obscured the summit crater rim. During one low pass over the lake, no signs of bubbling or upwelling were observed. Two patches of brown scum 2-3 m (6.5-10 ft) across floated in the approximate area where bubbling was observed earlier in the summer (see fig. 44 in original text). No signs of recent lake level disturbance or hydrothermal activity were noted."