Obtaining Absolute Locations for Quarry Seismicity Using Remote Sensing Data

We obtain absolute locations for 19 clusters of mining-induced seis- micity in southern California by identifying quarries using remote sensing data, in- cluding optical imagery and differential digital elevation models. These seismicity clusters contain 16,574 events from the Southern California Seismic Network from 1984 to 2002, which are flagged as quarry blasts but without any ground-truth lo- cation constraints. Using georeferenced airphotos and satellite radar topography data, we identify the likely sources of these events as quarries that are clearly visible within 1 to 2 km of the seismically determined locations. We then shift the clusters to align with the airphoto images, obtaining an estimated absolute location accuracy of 200 m for the cluster centroids. The improved locations of these explosions should be helpful for constraining regional 3D velocity models.