The 1996 Peru tsunamigenic earthquake: Broadband source process
Por:
Ihmlé P.F., Gomez J.-M., Heinrich P., Guibourg S.
Publicada:
1 ene 1998
Resumen:
We investigate the spatio-temporal complexity of moment release of the February 21, 1996 Peru earthquake (Mw 7.5). 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 30×30 km2 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. Copyright 1998 by the American Geophysical Union.
Filiaciones:
Ihmlé P.F.:
Institute of Geophysics, ETH-Hönggerberg, Zurich, Switzerland
Institut für Geophysik, Eidgenössische Technische Hochschule-Hönggerberg, 8093 Zürich, Switzerland
Gomez J.-M.:
Laboratoire de Géologie, Ecole Normale Supérieure, U. R. A. 1316, Paris, France
Laboratoire de Géologie, Ecole Normale Supérieure, U. R. A. 1316, 75231 Paris, France
Heinrich P.:
Laboratoire de Détection Géophysique, Commissariat à l'Energie Atomique, France
Laboratoire de Détection Géophysique, Commissariat à l'Energie Atomique, Bruyères-le-Châtel, France
Guibourg S.:
Laboratoire de Détection Géophysique, Commissariat à l'Energie Atomique, France
Laboratoire de Détection Géophysique, Commissariat à l'Energie Atomique, Bruyères-le-Châtel, France
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