2D Local Earthquake Tomography of Rayleigh Waves in Northwest of Iran
عنوان دوره: نوزدهمین کنفرانس ژئوفیزیک ایران
کد مقاله : 1631-NIGS
نویسندگان
کارشناسی ارشد ژئوفیزیک موسسه ژئوفیزیک دانشگاه تهران
چکیده
The tomography method of local earthquakes is of great use for studying the structure of the crust and upper mantle. In this research, two-dimensional surface wave tomography has been used to create tomographic maps for the Northwest of Iran plateau. For this sake, using 1961 local events recorded at 27 seismic stations of Iranian Seismological Center (IRSC) and International Institute of Earthquake Engineering and Seismology (IIEES) have been analyzed. In the first step, the fundamental mode of Rayleigh’s waves dispersion curves is obtained. Second, by using a 2D-linear inversion procedure, the group velocity tomography maps are achieved. In this study, the northwest of Iran, the region is divided into 0.50 ×0.50 cells. Low-velocity anomalies beneath Sahand and Sabalan ash cones, in other words long periods, is indicated from the results of surface wave tomography which is correlated with geological setting. The reason of that is the region, the northwest of Iran, is enclosed with low shear wave velocity such as quaternary deposits. In addition, other parameters are of paramount importance in terms of North Tabriz Fault existing, partial melting, and high temperature anomalies are beneath Sahand and Sabalan.
کلیدواژه ها
Title
2D Local Earthquake Tomography of Rayleigh Waves in Northwest of Iran
Authors
Somayeh Shakiba
Abstract
The tomography method of local earthquakes is of great use for studying the structure of the crust and upper mantle. In this research, two-dimensional surface wave tomography has been used to create tomographic maps for the Northwest of Iran plateau. For this sake, using 1961 local events recorded at 27 seismic stations of Iranian Seismological Center (IRSC) and International Institute of Earthquake Engineering and Seismology (IIEES) have been analyzed. In the first step, the fundamental mode of Rayleigh’s waves dispersion curves is obtained. Second, by using a 2D-linear inversion procedure, the group velocity tomography maps are achieved. In this study, the northwest of Iran, the region is divided into 0.50 ×0.50 cells. Low-velocity anomalies beneath Sahand and Sabalan ash cones, in other words long periods, is indicated from the results of surface wave tomography which is correlated with geological setting. The reason of that is the region, the northwest of Iran, is enclosed with low shear wave velocity such as quaternary deposits. In addition, other parameters are of paramount importance in terms of North Tabriz Fault existing, partial melting, and high temperature anomalies are beneath Sahand and Sabalan.
Keywords
Local Earthquake Tomography (LET), dispersion curves, Rayleigh wave