UNIVERSITY OF UTAH

Coincident with the arrival of low-frequency, large-amplitude surface waves of the Mw 7.9 Denali fault earthquake (DFE), an abrupt increase in seismicity was observed in the Yellowstone National Park region, despite the large epicentral distance of 3100 km. Within the first 24 hr following the DFE mainshock, we located more than 250 earthquakes, which occurred throughout the entire Yellowstone National Park region. The elevated seismicity rate continued for about 30 days and followed a modified Omori law decay with a P value of 1.02 # 0.07. For a declustered earthquake catalog, the seismicity following the 2002 DFE uniquely stands out with a significance of 30r. The increase in seismicity occurred over all magnitude bands. In general, we observed that seismicity following the DFE outlined the spatial pattern of past seismicity routinely observed in the Yellowstone National Park region. However, we found significant differences in triggered seismicity inside and outside the caldera...

Also known as: U of U Seismology and Active Tectonics Research Group