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摘要
This paper presents a simplified technique to simulate strong ground motion from a finite source of an earthquake. The simplified technique is based on modifications made in the semi empirical technique given by Midorikawa [1993] and later modified by Joshi and Midorikawa [2004]. Modifications in this technique have been made to consider the effect of radiation pattern and seismic moment of the target earthquake. The coastal region of Sumatra Island was struck by a great earthquake of magnitude 9.0 (M-w) on 26th December, 2004. This earthquake is known for its release of high amount of energy and the devastating Tsunami. This earthquake was recorded at several broadband stations including a nearest broadband station located in Indonesia. The source of this earthquake is modeled by a finite rectangular rupture plane. Various locations of nucleation point and different values of rupture velocity have been tested before finalizing the rupture responsible for this earthquake. Iterative modeling and comparison of simulated and observed record due to final model suggests that the rupture initiated at the western end of the rupture plane at a depth of 38km and started propagating in all direction with a rupture velocity of 3.0km/s. The final model has been used to simulate record at MDRS and VISK stations located at the coastal region of India and simulated records are compared with observed records at these stations. The comparisons confirm the suitability of final model for predicting strong ground motion and the efficacy of the approach in modeling great earthquake. Strong ground motion has been simulated for the Sumatra earthquake of 26th December, 2004 at various hypothetical stations surrounding the final model of rupture plane. The distribution of peak ground acceleration in the near source region has been computed from simulated record at these stations. The isoacceleration contours shows that high peak acceleration zones of the order of %26gt;2g are observed in the source zone of this earthquake which gradually decreases with distance. Using the parameters of final model of the Sumatra earthquake a great hypothetical earthquake at northern segment of Andaman ridge has been modeled and records have been simulated at Port Blair (POR) station located in the Andaman Island, India. The simulated records shows that peak ground acceleration of the order of 1.4g can be observed at POR station due to a hypothetical earthquake in the Andaman Island suggesting high seismic hazard in this region.
- 出版日期2012-12
