Spatially linked asperities of the 2006-2007 great Kuril earthquakes revealed by GPS

In 2006-2007, two great earthquakes ruptured the center of the Kuril subduction zone: first, the interplate thrust event, then the intraplate extensional event on the outer rise. The affected region was a seismic gap since 1915. Published patterns of slip differ for various seismic and tsunami inversions. The surface offsets that we measured with GPS on the Kuril Islands are sensitive to the total slip, including slow components beyond the seismic and tsunami band. We invert coseismic offsets and show that the asperities, or regions of high slip, are spatially linked for both earthquakes; this pattern suggests (although does not prove) that the first event triggered the second. For the 2006 earthquake, the asperity is very shallow, probably because of the absence of an accretionary prism. For the 2007 earthquake, our modeling suggests that the rupture occurred in the bent Pacific lithosphere to a depth of similar to 50 km. Citation: Steblov, G. M., M. G. Kogan, B. V. Levin, N. F. Vasilenko, A. S. Prytkov, and D. I. Frolov (2008), Spatially linked asperities of the 2006-2007 great Kuril earthquakes revealed by GPS, Geophys. Res. Lett., 35, L22306, doi: 10.1029/2008GL035572.