M Amighpey; B Vosooghi; M Motagh
Abstract
An earthquake with the magnitude of 5.9 ML shocked the Qeshm island located in the Persian Gulf on 27 November, 2005 at 13:53:22 local time. The earthquake occurred due to the reactivation of a NE-SW fault with a major reverse mechanism accompanied by a minor strike-slip component. Another earthquake ...
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An earthquake with the magnitude of 5.9 ML shocked the Qeshm island located in the Persian Gulf on 27 November, 2005 at 13:53:22 local time. The earthquake occurred due to the reactivation of a NE-SW fault with a major reverse mechanism accompanied by a minor strike-slip component. Another earthquake of 5.5 MW occurred on the same day at ca. 20:00 local time. The interesting feature of this earthquake is that the calculated mechanism for its strongest aftershock, which occurred ca. 6 hours after the main-shock, was a strike-slip mechanism that is completely different from the pure reverse mechanism for the main-shock. This study uses inversion of InSAR observation of earth surface displacement field boundary values to solve parameters of these 2 earthquakes. The results show activation of southern part of the Qeshm fault caused by the first earthquake along 7 km of its length. This event induced the second earthquake by activation of another strike-slip fault which is parallel to the Gavarzin anticline. Estimated slip was 96 cm for the first earthquake and 9 cm for the second one. Based on the estimated parameters of the these 2 earthquakes, the maximum displacement induced by the first earthquake was 6.7 cm in west, 4.6 cm in south and 16.4 cm in vertical directions on the earth surface. The maximum displacement of the second earthquake in west, south and vertical directions were 1.3, 1.6 and 1.4 cm respectively.
S Shokrzade; B Voosoghi; M Amighpey
Abstract
In this paper, the Bam post-seismic annual deformations in period from 2004 to 2010 have been obtained using synthetic aperture radar interferometry. The time series of deformations have been constructed using Persistent Scatterer Radar Interferometry technique. When displacements rate in the area are ...
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In this paper, the Bam post-seismic annual deformations in period from 2004 to 2010 have been obtained using synthetic aperture radar interferometry. The time series of deformations have been constructed using Persistent Scatterer Radar Interferometry technique. When displacements rate in the area are low and the pixels are with temporal decorrelation, this technique is more effective. The technique also largely reduces the topography residuals and atmospheric delay. Because of the low rates of post-seismic displacements, this technique is very useful for measuring such earth surface displacements. The results illustrate that the maximum amount of uplift and subsidence displacements for Line Of Sight (LOS) direction during 2004 to 2010 after the earthquake are 4.5± 0.5 and -4.3± 0.5 centimeter, respectively. Comparison of displacement fields demonstrates that the displacements reduction rates are approaching to the co-seismic phase. In addition, the results of post-seismic modeling proves that displacements field, follows exponential or logarithmic function.
