Fourpeaked volcano (United States) - Smithsonian / USGS Weekly Volcanic Activity Report for 27 September-3 October 2006 (New Activity / Unrest)

Volcanic unrest continued at Fourpeaked volcano during 23-29 September. Satellite observations by scientists from the University of Maryland-Baltimore County indicate that sulfur dioxide emission was continuing. Early in the week, AVO conducted several helicopter and fixed-wing missions during which observers photographed a linear series of vents running N from the summit for about 1 km.
Some of the vents were vigorously emitting steam and other volcanic gases. Thermal measurements of up to 75°C were recorded at the vents, although steam was likely obscuring hotter areas. Adjacent glacial ice had been disrupted and showed signs of subsidence.
Airborne gas measurements taken on 23, 24, and 30 September documented high emission rates of sulfur dioxide, hydrogren sulfide, and carbon dioxide, and a distinct sulfur smell was evident up to 50 km from the summit. An AVO status report on 3 October noted that cloudy conditions had prevented visual or satellite observations, but limited seismic data now being received did not indicate significant volcanic activity.

Source: US Geological Survey Alaska Volcano Observatory (AVO)
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From: Global Volcanism Program, 2006. Report on Fourpeaked. In: Mayberry, G (ed.), Weekly Volcanic Activity Report 27 September-3 October 2006. Smithsonian Institution and US Geological Survey.