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Vp/Vs ratios in the Yellowstone National Park region, Wyoming

January 1, 1985

In this paper we study the variation of Vp/Vs and Poisson's ratio (??) in the Yellowstone National Park region, using earthquakes which were well recorded by a local seismic network. We find that the average Vp/Vs value within the geothermally active Yellowstone caldera is about 7% lower than in the area outside the caldera. Within the caldera itself there may be a further 2-7% reduction of Vp/Vs in the hydrothermally active Norris Geyser Basin, the Upper and Lower Geyser Basins, and the Yellowstone Lake and Mud Volcano regions. After considering various possible causes for Vp/Vs changes, such as geologic and structural differences, thermal effects, partial melting, and hydrothermal activity, we conclude that the most plausible explanation for the observed Vp/Vs reduction is the presence of hot-water at temperatures and pore-pressures near the water steam transition in the caldera geothermal reservoirs. ?? 1985.

Publication Year 1985
Title Vp/Vs ratios in the Yellowstone National Park region, Wyoming
Authors S.N. Chatterjee, A. M. Pitt, H.M. Iyer
Publication Type Article
Publication Subtype Journal Article
Series Title Journal of Volcanology and Geothermal Research
Index ID 70013112
Record Source USGS Publications Warehouse