Search for a short-term transient deformation prior to the 2011 great Tohoku earthquake using GPS high-resolution positioning
Abstract
This study intends to provide observational constrains on the physical processes of earthquake initiation. More specifically, we investigate the possible occurrence of a transient deformation resulting from offshore slip in the hypocentral area within the hours preceding the Mw 9.0 2011 Tohoku-Oki earthquake offshore Japan. We analyse high-rate (1-Hz) coordinate time series from hundreds of GPS receivers of the dense continuously receiving GPS network GEONET. The GPS positions were processed using two methods in Precise Point Positioning (PPP) mode based on the GIPSY/OASIS II v 6.0 software (Jet Propulsion Laboratory) and the GINS software (french national space agency CNES). We search for a pattern spatially coherent with the surface deformation induced by a thrust event occurring at the subduction interface. We conclude that if any short-term (~2 hours long) aseismic preslip has occured in the epicentral region, then its equivalent magnitude has to be lower than Mw=6.7.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2013
- Bibcode:
- 2013AGUFM.G23B0789R
- Keywords:
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- 1207 GEODESY AND GRAVITY Transient deformation;
- 0520 COMPUTATIONAL GEOPHYSICS Data analysis: algorithms and implementation