| Abstract: | In-place measurements of environmental magnetic susceptibility of pyroclastic flows, surges and lahars emplaced during the 2006 eruption of Augustine Volcano show that primary volume magnetic susceptibilities of pyroclastic materials decreased where the flows encountered water and steam. The Rocky Point pyroclastic flow, the largest flow of the eruption sequence, encountered a small pond near the north coast of Augustine Island where local interactions with water and steam caused susceptibilities to decrease from 1,084+128x10-5 SI to 615+114x10-5 SI. Ash produced during phreatic explosions and pyroclastic surges that crossed snow also produced deposits with reduced susceptibilities, while lahar deposits derived from pyroclastic flows showed even greater reductions in susceptibility (430+129x10-5 SI). The susceptibility reductions are probably largely attributable to oxidation of iron in magnetite and other minerals within the pyroclastic flows, although other physiochemical processes may play a role. Measurements of the magnetic properties of pyroclastic flows, surges, and lahar deposits can be a useful tool in understanding the processes that occur when pyroclastic flows encounter ice, snow, and water and interact with water and steam on the slopes of active volcanoes. |
| Genre: | USGS Numbered Series |
| ProdID: | 98940 |
| Citation Author: | Beget, James E. |
| Citation Contributing Office: | Alaska Volcano Observatory |
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| Citation Language: | ENGLISH |
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| Citation No Pagination: | N |
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| Citation Online Only Flag: | Y |
| Citation Phsyical Description: | 15 p.; p. 269-283 |
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| Citation Public Comments: | Chapter 11 of Power, J.A., Coombs, M.L., and Freymueller, J.T., eds., The 2006 eruption of Augustine Volcano, Alaska |
| Citation Publisher: | U.S. Geological Survey |
| Citation Series: | Professional Paper |
| Citation Series Code: | PP |
| Citation Series Number: | 1769-11 |
| Citation Search Results Text: | Characterizing Pyroclastic-Flow Interactions with Snow and Water Using Environmental Magnetism at Augustine Volcano; 2010; PP; 1769-11; Beget, James E. |
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| Citation Year: | 2010 |
| Type: | citation/reference |
| Text: | Characterizing Pyroclastic-Flow Interactions with Snow and Water Using Environmental Magnetism at Augustine Volcano; 2010; PP; 1769-11; Beget, James E. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/usgs_thumb.jpg |
| URL (INDEX PAGE): | http://pubs.usgs.gov/pp/1769/ |
| Date Other: | Thu, 16 Dec 2010 00:00 -0600 |
| Publisher: | U.S. Geological Survey |
