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.

發文機構：Department of Civil Engineering

關鍵詞：東北地區地殼淺部衰減特性S波日本頻率依賴性地震危險性評估地震深度TohokuGeneralized inversion technique Non-parametric attenuation functionSeismic quality factorS-wave

分類號： P315.4[天文地球—地震學][天文地球—固體地球物理學][天文地球—地球物理學]TU196.1[建筑科學—建筑理論]