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This point feature class includes relocated earthquake hypocenters throughout the state of Washington. For each event, there are calculated latitude and longitude coordinates, a calculated depth, an oberved date and time, and a determined magnitude. Earthquake data was obtained from the Pacific Northwest Seismic Network (PNSN) (Steve Malone, 2011, written commun.). The earthquake hypocenter relocation method used in this study uses the double-difference algorithm of Waldhauser and Ellsworth (2000). This algorithm is based on the ray paths from two earthquakes close to a common station being almost identical, and the difference in observed travel time can therefore be attributed with a high accuracy to the spatial offset of the two earthquakes (Waldhauser and Ellsworth, 2000). This study uses a hypocenter relocation computer program developed by Felix Waldhauser of the United States Geological Survey (USGS) called hypoDD,that applies this concept to a cluster of earthquakes and determines the offset between each earthquake relative to one another. Funding for this data compilation was provided through a U.S. Department of Energy geothermal grant. |