Historic Earthquakes: Finite Fault Model
Magnitude 7.3 PAPUA, INDONESIA
2004 February 07 02:42:35 UTC
Preliminary Rupture Model
Contributed by Chen Ji, Caltech
Introduction
Nineteen broadband seismograms were selected from a realtime dataset
provided by NEIC data center to study this earthquake. The Green's functions
were generated by using a crust model interpolated from crust2.0 model
[Laske et al., 2001] at the PDE hypocenter location. A simulated annealing
finite inversion procedure using wavelet transform [Ji et al., 2002] was
applied to investigate the spatial-temporal rupture history of this
earthquake. Two fault planes were first built by using the moment tensor
solution of Caltech [Polet, 2004]. Finite fault inversions were then
preformed simultaneously to find the plane that fits the data better.Both of
them explain the data well but the fault plane (strike= 355, dip=80) is
better.
Result:
The inverse result explains data well (Figure 1.). The seismic moment of
this earthquake is 9.8x10^26 dyne.cm, or a moment magnitude of 7.25.
Figure 1: Earthquake Location
Comparison of teleseismic body waves (black) and
synthetic seismograms (red). The epicenter distance and azimuth of each
station are indicated at the beginning portion of records with the azimuth
above. The peak amplitude of each record is showed above end of each trace
in micrometer and used to normalize both data and synthetic seismogram.
Finite fault slip distribution. The color
shows the slip amplitude and contour in 5 sec interval shows the rupture
front.
