The Seismological Society of America (SSA) is an international scientific society devoted to the advancement of seismology and its applications in understanding and mitigating earthquake hazards and in imaging the structure of the earth.
The second largest earthquake swarm ever recorded in Yellowstone National Park occurred during the two weeks from 27 December 2008 and 7 January 2009 and included more than 1000 earthquakes. Analysis of the swarm suggests epicenters migrated north over the 12 day period and maximum hypocenter depths abruptly shallowed from 12 km to 3 km depth at the time of rapid cessation of activity on Jan. 7. Source properties of the swarm earthquakes suggest that the swarm may be due to the movement of hydrothermal fluids through pre-existing cracks, as suggested by recent analysis by University of Utah scientists.
The Yellowstone Volcano Observatory (YVO) was created as a partnership among the U.S. Geological Survey (USGS), Yellowstone National Park, and University of Utah to strengthen the long-term monitoring of volcanic and earthquake unrest in the Yellowstone National Park region. Yellowstone is the site of the largest and most diverse collection of natural thermal features in the world and the first National Park.