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Title:: Study of Attenuation Characteristics of the Complex Tectonic Region Based on Generalized Inversion Method

作者:: 周影¹; 2; 王宏伟^<sup>1; 2; 温瑞智¹; 2; (1.中国地震局工程力学研究所,黑龙江哈尔滨 150080; 2.中国地震局地震工程与工程振动重点实验室,黑龙江哈尔滨 150080)

Author(s):: ZHOU Ying¹; 2; WANG Hongwei¹; 2; WEN Ruizhi¹; 2; (1.Institute of Engineering Mechanics,China Earthquake Administration,Harbin 150080,Heilongjiang,China;2.Key Laboratory of Earthquake Engineering and Engineering Vibration of China Earthquake Administration,Harbin 150080,Heilongjiang,China)

Keywords:: Generalized Spectral Inversion method; the Kanto basin; strong ground motion; attenuation characteristics; quality factor

摘要:: 为研究构造复杂的关东盆地及其周边地区的地震动衰减特性,根据地震震源机制解和Slab1.0模型,依据前人提出的日本地区地震构造类型划分方法给出所研究地震的构造类型,并依据地震构造类型及空间分布划分了3个研究区域。利用单步非参数化广义谱反演方法分析了3个区域的地震动衰减特性。结果表明:区域Ⅰ中发生于陆地的浅地壳地震的地震动路径衰减较弱,远距离处近似不出现路径衰减,频率相关的非弹性衰减较弱,品质因子Q=92.33f^1.87; 区域Ⅱ中,发生于陆地的上地幔地震的地震动路径衰减的下降速率随距离增大而增大,频率相关的非弹性衰减较强,Q=27.75f^1.08; 区域Ⅲ中,发生于近海的浅层地壳和上地幔地震的地震动路径衰减兼具区域Ⅰ、Ⅱ的衰减属性,Q=58.07f^0.89。

Abstract:: In order to study the characteristics of the ground motion attenuation of the complex plate tectonics of the Kanto basin and its vicinity in Japan,on the basis of the focal mechanism and Slab1.0 model,and according to the earthquake classification scheme adapted for Japan proposed by previous studies,we decided the categories of the earthquake events,and on this basis we further divided the study region into three parts.Then we used the method of One-step Nonparametric Generalized Spectrum Inversion to analyze the attenuation characteristics of ground vibrations in the three regions.The results show that in Region 1,the path attenuation of the ground motion of the shallow-crust earthquakes occurring inland is weak; there is almost no attenuation in long distance.The frequency-dependent inelastic attenuation is also weak.The quality factor Q=92.33f ^1.87.In Region 2,the decay rate of the path attenuation of the upper-mantle earthquake inland increases with the increase of distance.The frequency-dependent inelastic attenuation is stronger.The quality factor Q=27.75f^1.08.In Region 3,the path attenuation of the ground motion of the shallow-crust and upper-mantle earthquakes in the offshore area has the same attributes of the path attenuation in the first two regions.The quality factor Q=58.07f ^0.89.