آنالیز تغییر شکل سطحی زمین در اثر زلزله 6 آذر 1384 جزیره قشم با استفاده از تصاویر راداری

Abstract

An earthquake with the magnitude of 5.9 Mw occurred in Qeshm Island and Hormozgan province in November 27th 2005. 3D co-seismic deformation field caused by the earthquake are determined based on the ascending and descending interferograms and azimuth offsets. The peak to peak estimated displacement is about 10 cm in west, 69 cm in north and 22 cm in vertical directions. We apply strain analysis to study coseismic deformation of the earthquake. Finite element method as numerical solutions is applied in order to compute the strain tensors. Furthermore, dilation and shear parameters are derived from computed strain tensor fiel of the area. The maximum expansion and contraction are computed as 0.006 and 0.005, respectively. Moreover, the maximum shears in xy, xz and yz planes obtained by finite element method were 0.2 rad, 0.4 rad and 0.19 rad, respectively. The results represent the changes in direction and maximum expansion and maximum contraction in the direction of faults proposed by aftershock seismicity study of the earthquake. The concentration of the shear and dilation are observed in central part of island along the NW-SE oriented fault passing from central part of island. The numerical results show considerable amounts of shear and dilation in the vicinity of Qeshm fault, as well.