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AGU: Geophysical Research Letters

 

Keywords

  • subduction zones
  • asperities
  • coseismic displacements

Index Terms

  • Geodesy and Gravity: Transient deformation
  • Geodesy and Gravity: Satellite geodesy: results
  • Geodesy and Gravity: Seismic cycle related deformations
  • Seismology: Earthquake interaction, forecasting, and prediction
  • Seismology: Subduction zones

Abstract

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

Grigory M. Steblov

Institute of Physics of the Earth, Russian Academy of Sciences, Moscow, Russia

Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York, USA

Mikhail G. Kogan

Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York, USA

Boris V. Levin

Institute of Marine Geology and Geophysics, Far Eastern Branch, Russian Academy of Sciences, Yuzhno-Sakhalinsk, Russia

Nikolai F. Vasilenko

Institute of Marine Geology and Geophysics, Far Eastern Branch, Russian Academy of Sciences, Yuzhno-Sakhalinsk, Russia

Alexander S. Prytkov

Institute of Marine Geology and Geophysics, Far Eastern Branch, Russian Academy of Sciences, Yuzhno-Sakhalinsk, Russia

Dmitry I. Frolov

Ioffe Physico-Technical Institute, Russian Academy of Sciences, St. Petersburg, Russia

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 ∼50 km.

Received 3 August 2008; accepted 17 October 2008; published 27 November 2008.

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.

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