Double seismic zone in the Hokkaido Island, Southern Kurile arc, derived from off-Kushiro permanent OBS and land-based observations

We located hypocenters for more than two years, using combined datasets from land-based observations and ocean-bottom seismological data acquired by a permanent cable geophysical observatory system (JAMSTEC system), installed off Kushiro-Tokachi in July 1999. Hypocenter distribution characterizes that: 1) double seismic zone just east of the cabled observatory system, 2) a relatively low seismicity west of the cabled system, and 3) characteristic shallow seismic activity below the cabled system.