Seismic cycle in Taiwan derived from GPS measurements

The present-day displacement field in Taiwan based on geodetic measurements is interpreted in terms of seismic cycle strain fields due to the subduction of the China margin. We model the surface displacements, using dislocation theory, as due to variable slip on buried faults in an elastic half-space. The interseismic velocities are interpreted as a seismic slip on a 10 km deep 'decollement' leading to strain accumulation on the locked Chelungpu thrust fault (CTF), and on the partly locked Longitudinal Valley fault. The slip model on the CTF that we obtain for the Chichi earthquake, is consistent with some of the main features of the slip distribution seen in seismological and geological results. The slip increases both toward the surface and northward. The inferred WNW- ESE northern end of the rupture surface coincides with the Sanyi transfer fault zone. We conclude that the results obtained are compatible with a simple model of subduction of the Chinese margin. 2001 Academie des sciences / Editions scientifiques et medicales

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