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Inversion of high‐rate (1 sps) GPS data for rupture process of the 11 March 2011 Tohoku earthquake (M w 9.1)
Author(s) -
Yue H.,
Lay T.
Publication year - 2011
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2011gl048700
Subject(s) - geology , hypocenter , geodesy , seismology , global positioning system , slip (aerodynamics) , geodetic datum , inversion (geology) , seismic moment , trench , smoothing , tectonics , fault (geology) , induced seismicity , physics , mathematics , materials science , computer science , statistics , telecommunications , layer (electronics) , composite material , thermodynamics
The space‐time fault displacement history of the 11 March 2011 Tohoku (M w 9.1) megathrust earthquake is obtained by least‐squares inversion of high‐rate (1 sample per second) GPS ground motions recorded in Japan. Complete near‐source time‐varying and static ground motions for periods ≥25 s are fit in the inversion using a normal mode formalism to compute the Green functions. The basic rupture pattern is stable for various choices of model parameters and solution smoothing, and excellent fits to the complete seismo‐geodetic ground motions are obtained. The preferred solution has concentrations of slip near the trench and hypocenter, with sub‐fault source time function durations of ∼30–70 s and maximum slip of ∼60 m. Down‐dip slip spreads over a wider area with smaller maximum slip (<∼10–15 m). Inversion of the high‐rate GPS data exploits both the timing and total displacement information in the ground motions, yielding stable estimates of the seismic moment (∼4.8 × 10 22 Nm; M w = 9.1) and slip distribution.