2009 Jan 03 Irian Jaya, Indonesia, Earthquakes

ERI topics site (English) / ERI topics site (Japanese)

January 06, 2009
Strong Motion Seismology Group

Overall Comments

An earthquake doublet occurred on January 03, 2009 (UT) near the northern coast of Papua (Irian Jaya), Indonesia. The eastern area of the source region is famous for frequent occurrence of earthquake doublets due to the complex tectonic settings (e.g. Lay and Kanamori, 1980; Park and Mori, 2007).

To investigate source processes of the earthquakes, we have performed teleseismic waveform inversions of Kikuchi and Kanamori (1991) using displacement records observed at stations of FDSN from IRIS DMC. We fixed the epicenters determined by USGS and searched the focal depths to minimize the waveform fit. The residuals of the finite fault inversions preferred low-angle south-dipping fault planes for both the earthquakes. Significant slip exceeding 5 m appears near the each hypocenter, and the slip distribution of the earthquake doublet seems to be complementary.

Note that the rupture starting point of the 2nd event is close to the edge of the slip distribution of the 1st event.



Slip Distribution of Mw 7.6 and Mw 7.4 Earthquakes





Mw 7.6 Earthquake on 2009 Jan 03 19:43:54 (UT)
Source Time Function, Moment Tensor, Inverted Slip, and Waveform Fit






Mw 7.6 Earthquake on 2009 Jan 03 19:43:54 (UT)
Stations used for the Teleseismic Waveform Inversion





Mw 7.4 Earthquake on 2009 Jan 03 22:33:42 (UT)
Source Time Function, Moment Tensor, Inverted Slip, and Waveform Fit






Mw 7.4 Earthquake on 2009 Jan 03 22:33:42 (UT)
Stations used for the Teleseismic Waveform Inversion





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