Waveform Modeling of Earthquake Data for Delineating the Sedimentary Structure of the Anchorage Basin, Alaska

摘要：

The paper presents waveform inversion technique using the local earthquake data to estimate the crustal structure of the Anchorage basin, Alaska. Three component recorded data of an earthquake (ML= 4.8) from 26 strong motion station sites in Anchorage area are used for this purpose. The technique uses parallelized reflectivity method to compute synthetic seismograms of SH-, SV-, and P- wave motions and implements global optimization technique based on simulated annealing inversion to fit the observed waveform data with the computed seismograms. The inversion searches for optimal values of four model parameters namely the layer thickness, P-wave velocity, P to Swave velocity ratio and density at each site. The inversion shows that the crustal thickness of the Anchorage basin is around 40 km with P- and S-wave velocity at the bottom of the crust is around 6.4 km/s and 3.8 km/s, respectively. It is noticed that the observed ground motions of the Anchorage basin are strongly affected by the S-wave velocities of the shallow (< 0.1 km) sediments. The P-wave amplification due to the basin sediments is not significant. The presence of low S-wave velocity zones primarily responsible for the observed variations of the ground motions characteristics within the Anchorage basin. The P-to-S-wave velocity ratio varies from 10.0 to 2.0 for the shallower parts of the basin and remains around 1.78 in the deeper parts of the basin.

关键词： Waveform inversion sedimentary basin P and S-wave velocity simulated annealing

作者: U. Dutta M. K. Sen N. N. Biswas Z. Yang

作者单位: Department of Civil Engineering, University of Alaska Anchorage, 3211 Providence Dr., Anchorage, AK Jackson School of Geosciences, University of Texas at Austin, 10100 Burnet Road Building 196, TX 787 Geophysical Institute, University of Alaska Fairbanks, PO BOX 757320, Fairbanks, AK 99775, USA.

会议类型: 国际会议

会议名称: 14th World Conference on Earthquake Engineering(第十四届国际地震工程会议)

会议地点: 北京

会议语种:英文

在线出版日期: 2008-10-12（万方平台首次上网日期，不代表论文的发表时间）