Publication Date:
1998
Description:
We investigate the spatio-temporal complexity of moment release of the
February 21, 1996 Peru earthquake (Mw7.5). We use a non-linear source tomographic
technique, based on simulated annealing, to invert surface wave source spectra for the
slip distribution on a gently dipping fault plane. The spectra (5-65 mHz) are obtained
using an empirical Green's function (EGF) method applied to first and second orbit
fundamental mode Rayleigh waves. Spectra are well fit by a 110 km bilateral rupture,
subparallel to the trench, updip of the hypocenter, with a total moment of 2.0?1020 Nm.
The non-linear inversion reveals a 30x30 km 2 major slip patch south the onset, where
rupture velocities attain 1.5-2.0 km/s. Inversions of teleseismic broadband P and SH
waves (10-500 mHz) indicate little or no directivity, consistent with the surface wave
data. The average source time functions for both the surface and body wave data are
similar in shape and in duration (?50 s). Part of the slip during the 1996 Peru event
occurred in a region of reduced background seismicity, as was the case for the 1992
Nicaragua slow event, suggesting that the seismogenic potential of low seismicity
regions near the trench should be globally reassessed
Keywords:
Earthquake
;
Tsunami(s)
;
Broad-band
;
Source
;
GRL
;
3630
;
Mineralogy,
;
Petrology,
;
and
;
Mineral
;
Physics:
;
Experimental
;
mineralogy
;
and
;
petrology
;
3924
;
Mineral
;
Physics:
;
High-pressure
;
behavior
;
7218
;
Seismology:
;
Lithosphere
;
and
;
upper
;
mantle
;
8124
;
Tectonophysics:
;
Earth's
;
interior--composition
;
and
;
state
;
(old
;
8105)
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