Muzaffarabad earthquake of 8 October 2005 (Mw 7.6): A preliminary report on source characteristics and recorded ground motions
Por:
Singh S.K., Iglesias A., Dattatrayam R.S., Bansal B.K., Rai S.S., Perez-Campos X., Suresh G., Baidya P.R., Gautam J.L.
Publicada:
1 ene 2006
Resumen:
We present a preliminary source study of the Muzaffarabad earthquake of 8 October 2005 (Mw 7.6) and the far-field ground motions that it generated. Our analysis is based on regional broadband seismograms recorded at stations operated by the India Meteorological Department (IMD) which are situated to the south of the epicentre, and at non-IMD stations which are located to the north. We find that the source spectrum of the earthquake is reasonably consistent with ?2-source model with a seismic moment, M0, of 2.94 × 1020 N-m and a corner frequency, fc, of 0.051 Hz (Brune stress drop of 9.5 MPa). The radiated seismic energy, ER, estimated from the empirical Green's function (EGF) technique is 2.70 × 10 16 J. This yields a normalized radiated energy, ER/M 0, of 9.1 × 10-5, and an apparent stress, ?a, of 2.7 MPa. The rupture area of 100 × 15 km2 (estimated from slip distribution mapped from the inversion of teleseismic body waves) gives a static stress drop of about 11.3 MPa. From these source parameters we estimate a radiation efficiency of 0.49, implying a 'brittle' rupture typical of interplate events. Stochastic method requires a stress drop of ?10 MPa to explain the observed peak ground motions (Amax and Vmax) recorded at regional distances, and predicts Amax and Vmax exceeding 1 g and 100 cm/s, respectively at hard sites in the epicentral region. The source parameters and far-field ground motions of the Muzaffarabad and Bhuj earthquakes are quite similar even though the tectonic environment and the depth of their occurrence are distinct.
Filiaciones:
Singh S.K.:
Instituto de Geofísica, UNAM, CU, 04510 México, D.F., Mexico
Iglesias A.:
Instituto de Ingenieria, UNAM, CU, 04510 Mexico, D.F., Mexico
Dattatrayam R.S.:
India Meteorological Department, Lodhi Road, New Delhi 110 003, India
Bansal B.K.:
Department of Science and Technology, New Mehrauli Road, New Delhi 110 016, India
Rai S.S.:
National Geophysical Research Institute, Uppal Road, Hyderabad 500 007, India
Perez-Campos X.:
Instituto de Geofísica, UNAM, CU, 04510 México, D.F., Mexico
Suresh G.:
India Meteorological Department, Lodhi Road, New Delhi 110 003, India
Baidya P.R.:
India Meteorological Department, Lodhi Road, New Delhi 110 003, India
Gautam J.L.:
India Meteorological Department, Lodhi Road, New Delhi 110 003, India
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