Report on Fourpeaked (United States) — 11 October-17 October 2006
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 11 October-17 October 2006
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2006. Report on Fourpeaked (United States). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 11 October-17 October 2006. Smithsonian Institution and US Geological Survey.
58.77°N, 153.672°W; summit elev. 2105 m
All times are local (unless otherwise noted)
The AVO reported that earthquake activity and gas emissions continued at Fourpeaked during 7-13 October. Observations through most of the week were hindered due to cloud cover, but on 12 October AVO staff reported that two prominent vents were emitting steam and gas.
Geologic Background. Poorly known Fourpeaked volcano in NE Katmai National Park consists of isolated outcrops surrounded by the Fourpeaked Glacier, which descends eastward almost to the Shelikof Strait. The orientation of andesitic lava flows and extensive hydrothermal alteration of rocks near the present 2105-m-high summit suggest that it probably marks the vent of Fourpeaked volcano. Eruptive activity during the Holocene had not been confirmed prior to the first historical eruption of Fourpeaked in September 2006. A N-trending fissure extending 1 km from the summit produced minor ashfall.