Variable-slip rupture model of the great 1923 Kanto, Japan, earthquake: Geodetic and body-waveform analysis
Variable-slip rupture model of the great 1923 Kanto, Japan, earthquake: Geodetic and body-waveform analysis
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1923 年日本关东大地震的可变滑移破裂模型：大地测量和体波形分析
DOI：
10.1785/bssa0850010159
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发表时间：
1995
影响因子：
3
通讯作者：
P. Somerville
中科院分区：
文献类型：
--
作者：
D. Wald;P. Somerville
1923年关东地震（Ms = 8.1）的大地测量和地震观测数据集已被合并成一个联合反演的时间和空间滑动变化。我们假设一个初始断层模型与Kanamori（1971）根据初动数据、余震面积和近震距离面波振幅确定的几何形状一致，并包含Matsu'ura等（1980）根据本文所用大地测量数据估计的滑动面积。然后，我们反演了一个不均匀分布的断层平面的滑动。所使用的水准路线和三角测量站（由225个水准点和31个三角测量点组成）来自Matsu'ura等人（1980年）。我们选择首先通过单独反演大地测量数据来确定整体静态滑动分布。然后，我们开始逐渐增加地球物理数据的重要性，始终要求与大地水准测量和水平位移良好拟合。通过这种方式，我们可以提供一个约束的整体静态滑动特性从大地测量数据，并提供稳定性的地震波反演，但确定的程度滑动的不均匀性和时间历史最适合匹配的波形数据和模拟强地面运动。我们的分析得出的地震矩为7至8 × 1027达因-厘米（Mw = 7.8至7.9），最大滑动约为8米。最集中的滑动是在浅的中部和西部的断层。如Takeo和Kanamori（1993）所述，断层面上集中滑移的位置对所产生的地面运动的振幅、持续时间和频率成分有重要影响。
The available geodetic and teleseismic data sets for the 1923 Kanto earthquake (Ms = 8.1) have been combined into a joint inversion for both temporal and spatial slip variations. We assumed an initial faulting model to be consistent with the geometry determined by Kanamori (1971) on the basis of first-motion data, aftershock area, and the amplitude of surface waves at teleseismic distances and also to enclose the slipped area estimated by Matsu'ura et al. (1980) from the geodetic data employed here. We then inverted for a heterogeneous distribution of slip of the fault plane. The leveling routes and triangulation stations used (consisting of 225 bench marks and 31 triangulation points) are from Matsu'ura et al. (1980). We chose to first determine the overall, static slip distribution by inverting the geodetic data alone. We then proceeded to gradually increase the importance of the teleseismic data, always requiring a good fit to the geodetic leveling and horizontal displacements. In this way, we could provide a constraint on the overall static slip characteristics from the geodetic data and provide stability for the teleseismic inversion, yet determine the degree of slip heterogeneity and time history most suitable for matching the waveform data and for simulating strong ground motions. Our analysis yields a seismic moment of 7 to 8 × 1027 dyne-cm (Mw = 7.8 to 7.9) with a maximum slip of approximately 8 m. The most concentrated slip is in the shallow central and western portion of the fault. The location of the concentrated slip on the fault plane has important consequences for the amplitude, duration, and frequency content of the resulting ground motions as documented by Takeo and Kanamori (1993).