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Multiple CMT source analysis of the 2004 Sumatra earthquake
Author(s) -
Tsai Victor C.,
Nettles Meredith,
Ekström Göran,
Dziewonski Adam M.
Publication year - 2005
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 - 10.1029/2005gl023813
Subject(s) - seismology , moment tensor , geology , subduction , trench , moment magnitude scale , seismic moment , tsunami earthquake , interplate earthquake , seismic gap , slip (aerodynamics) , inversion (geology) , focal mechanism , aftershock , fault (geology) , tectonics , geometry , deformation (meteorology) , oceanography , chemistry , mathematics , organic chemistry , physics , layer (electronics) , scaling , thermodynamics
While it is agreed that the great Sumatra earthquake of December 26, 2004 was among the largest earthquakes of the past century, there has been disagreement on how large it was, which part of the fault ruptured, and how the rupture took place. We present a centroid‐moment‐tensor (CMT) analysis of the earthquake in which multiple point sources are used in the inversion to mimic a propagating slip pulse. The final model consists of five point sources, with the southernmost sources accounting for the majority of the moment release. The presumed fault planes of the southern sources strike northwest, while those in the north strike northeast, consistent with the geometry of the subduction trench. Slip on the fault is found to be more oblique in the north than in the south. The inversion with five sources leads to a moment magnitude for the Sumatra earthquake of M W = 9.3, consistent with estimates from long‐period normal‐mode amplitudes.