Crustal attenuation characteristics of S-waves beneath the Eastern Tohoku region, Japan

作者：Muhammad Adeel Arshad

摘要：An inversion method was applied to crustal earthquakes dataset to find S-wave attenuation characteristics beneath the Eastern Tohoku region of Japan.Accelerograms from 85 shallow crustal earthquakes up to25 km depth and magnitude range between 3.5 and 5.5were analyzed to estimate the seismic quality factor Q_s. A homogeneous attenuation model Q_s for the wave propagation path was evaluated from spectral amplitudes, at 24 different frequencies between 0.5 and 20 Hz by using generalized inversion technique. To do this, non-parametric attenuation functions were calculated to observe spectral amplitude decay with hypocentral distance. Then, these functions were parameterized to estimate Q_s. It was found that in Eastern Tohoku region, the Q_s frequency dependence can be approximated with the function 33 f~(1.22) within a frequency range between 0.5 and 20 Hz. However,the frequency dependence of Q_s in the frequency range between 0.5 and 6 Hz is best approximated by Q_s(f) = 36f~(0.94) showing relatively weaker frequency dependence as compared to the relation Q_s(f) = 6 f~(2.09) for the frequency range between 6 and 15 Hz. These results could be used to estimate source and site parameters for seismic hazard assessment in the region.

发文机构：Department of Civil Engineering

关键词：东北地区地壳浅部衰减特性S波日本频率依赖性地震危险性评估地震深度TohokuGeneralized inversion technique Non-parametric attenuation functionSeismic quality factorS-wave

分类号： P315.4[天文地球—地震学][天文地球—固体地球物理学][天文地球—地球物理学]TU196.1[建筑科学—建筑理论]