Refining Fault Structure and Seismic Behavior along the Kuril Islands, Russia, using Teleseismic Double-Difference Relocation

Along the Kuril-Kamchatka subduction zone, the Pacific Plate subducts beneath the Okhotsk Plate at ~80 mm/yr, and this seismically active region has historically produced great (M>8) earthquakes. Events include the 1952 Mw 9.0 event that ruptured a 700 km section of the plate boundary and generated an extensive tsunami, the 1963 Mw 7.8 and 1975 7.5 tsunami earthquakes, and an unusual M>8 doublet in 2006-2007 that involved a Mw 8.3 underthrusting earthquake followed two months later by an Mw 8.1 outer rise normal faulting event. The seismic behavior in this region indicates a plate boundary that has a complex megathrust seismogenic zone and additional hazard associated with the outer rise. A clearer understanding of seismogenesis along the subduction zone is possible using historical and global catalog seismicity data, provided we have confidence in the hypocenter locations. We present a revised catalog along the Kuril Islands (40° - 55°N; 145° - 165° W) calculated by teleseismic double-difference relocation (teleTomoDD) using P and S-wave data from 1900 through 2012. Initial phase data comes from the reviewed EHB catalog, the reviewed ISC bulletin, and the USGS NEIC, and we present comparisons using each catalog individually and combinations of catalogs. When waveforms are available, we use cross-correlation to determine more precise differential travel-times, including new correlation techniques with the potential for real-time application. Final event hypocenters show clustering of events, improved from the diffuse initial locations, and provide a refined picture of the seismogenic zone along the subducting slab boundary. We compare relocations to existing finite fault models, seafloor geology, and incoming plate bathymetry.