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Quantifying slip balance in the earthquake cycle: Coseismic slip model constrained by interseismic coupling
Author(s) -
Wang Lifeng,
Hainzl Sebastian,
Mai P. Martin
Publication year - 2015
Publication title -
journal of geophysical research: solid earth
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.983
H-Index - 232
eISSN - 2169-9356
pISSN - 2169-9313
DOI - 10.1002/2015jb011987
Subject(s) - slip (aerodynamics) , geology , seismology , geodetic datum , geodesy , episodic tremor and slip , borehole , subduction , geotechnical engineering , tectonics , physics , thermodynamics
The long‐term slip on faults has to follow, on average, the plate motion, while slip deficit is accumulated over shorter timescales (e.g., between the large earthquakes). Accumulated slip deficits eventually have to be released by earthquakes and aseismic processes. In this study, we propose a new inversion approach for coseismic slip, taking interseismic slip deficit as prior information. We assume a linear correlation between coseismic slip and interseismic slip deficit and invert for the coefficients that link the coseismic displacements to the required strain accumulation time and seismic release level of the earthquake. We apply our approach to the 2011 M 9 Tohoku‐Oki earthquake and the 2004 M 6 Parkfield earthquake. Under the assumption that the largest slip almost fully releases the local strain (as indicated by borehole measurements), our results suggest that the strain accumulated along the Tohoku‐Oki earthquake segment has been almost fully released during the 2011 M 9 rupture. The remaining slip deficit can be attributed to the postseismic processes. Similar conclusions can be drawn for the 2004 M 6 Parkfield earthquake. We also estimate the required time of strain accumulation for the 2004 M 6 Parkfield earthquake to be ~25 years (confidence interval of [17, 43] years), consistent with the observed average recurrence time of ~22 years for M 6 earthquakes in Parkfield. For the Tohoku‐Oki earthquake, we estimate the recurrence time of ~500–700 years. This new inversion approach for evaluating slip balance can be generally applied to any earthquake for which dense geodetic measurements are available.