on Iliamna Volcano, Alaska
environments. Iliamna Volcano is thus an ideal site to study such mass failures and its relation to volcanic activity. Available online at www.sciencedirect.com Journal of Volcanology and Geothermal Research 168 (2007) 114–136 www.elsevier.com/locate/jvolgeores⁎In this study, we present different me...
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| Language: | English |
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.462.2144 http://myweb.wwu.edu/~caplanj/pdf/huggel_etal_iliamna_jvgr.pdf |
| Summary: | environments. Iliamna Volcano is thus an ideal site to study such mass failures and its relation to volcanic activity. Available online at www.sciencedirect.com Journal of Volcanology and Geothermal Research 168 (2007) 114–136 www.elsevier.com/locate/jvolgeores⁎In this study, we present different methods that fit into a concept of (1) long-term monitoring, (2) early warning, and (3) event documentation and analysis of ice-rock avalanches on ice-capped active volcanoes. Long-term monitoring methods include seismic signal analysis, and space-and airborne observations. Landsat and ASTER satellite data was used to study the extent of hydrothermally altered rocks and surface thermal anomalies at the summit region of Iliamna. Subpixel heat source calculation for the summit regions where avalanches initiate yielded temperatures of 307 to 613 K assuming heat source areas of 1000 to 25 m2, respectively, indicating strong convective heat flux processes. Such heat flow causes icemelting conditions and is thus likely to reduce the strength at the base of the glacier. We furthermore demonstrate typical seismic records of Iliamna avalanches with rarely observed precursory signals up to two hours prior to failure, and show how such signals could be used for a multi-stage avalanche warning system in the future. For event analysis and documentation, space- and airborne observations and seismic records in combination with SRTM and ASTER derived terrain data allowed us to reconstruct avalanche dynamics and to identify remarkably similar failure and propagation mechanisms of Iliamna avalanches for the past 45 years. Simple avalanche flow modeling was able to reasonably replicate Iliamna avalanches and can thus be applied for hazard assessments. Hazards at Iliamna Volcano are low due to its remote location; however, we emphasize the transfer potential of the methods |
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