Strong-motion generation areas of a great subduction-zone earthquake: Waveform inversion with empirical Green's functions for the 2003 Tokachi-oki earthquake
Strong-motion generation areas of a great subduction-zone earthquake: Waveform inversion with empirical Green's functions for the 2003 Tokachi-oki earthquake
复制标题
DOI：
10.1785/0120060183
复制
发表时间：
2008-02-01
影响因子：
3
通讯作者：
Irikura, K.
中科院分区：
文献类型：
--
作者：
Nozu, A.;Irikura, K.
一种经验波形反演法。用格林函数估计了2003年日本东京8.3级地震的强震产生区。虽然基于低频(小于0.2赫兹)地面运动的波形反演已经揭示了这次大俯冲带地震的破裂过程，但从工程角度来看，更重要的是研究地震是如何产生更高频率的强地面运动的。由于在较高频率下计算实际的理论格林函数的难度较大，传统的反演方法不包括频率较高的波形数据。在这项研究中，借助经验格林函数，我们将波形反演的适用范围扩展到1赫兹以下的高频地震动。我们选择了三次余震进行分析，参考了主震和余震记录之间的成组延迟时间的相似性。合成的滑移模型有三个SMGA，每个都靠近所用的一次余震的震中。总的来说，本研究中确定的SMGA的位置与使用低频(低于0.2赫兹)地面运动加上大地测量数据和海啸的反演结果确定的凹凸体很好地吻合。这意味着高达1赫兹的强烈地面运动是由几乎相同的产生较低频率地面运动的凹凸体产生的。就滑移模型的复杂性而言，虽然我们的分析集中在高频上，但我们的滑移模型至少和传统的低频滑移模型一样简单。这些结果将有助于建立未来大俯冲带地震的震源模型，用于强震预测。
A waveform inversion with empirical. Green's functions was conducted to estimate strong-motion generation areas (SMGAs) of the 2003 Tokachi-oki, Japan, earthquake (M-w 8.3). Although the rupture process of this great subduction-zone earthquake has been revealed with waveform inversions based on low-frequency (lower than 0.2 Hz) ground motions, it is much more important from an engineering point of view to investigate how strong ground motions with higher frequencies were generated from the earthquake. Waveform data with higher frequencies have been excluded from the conventional inversions because of the difficulty in computing realistic theoretical Green's functions at higher frequencies. In this study, with the aid of empirical Green's functions, we extended the applicability of the waveform inversion to higher-frequency ground motions up to 1 Hz. We selected three aftershocks for use in the analysis, referring to the similarity of the group delay time between the mainshock and the aftershock records. The resultant slip model has three SMGAs, each of which is close to the hypocenter of one of the aftershocks used. Generally speaking, locations of the SMGAs identified in this study agree well with asperities identified from the inverted results using low-frequency (lower than 0.2 Hz) ground motions plus geodetic data and tsunamis. It implies that strong ground motions up to 1 Hz were generated from almost the same asperities producing lower-frequency ground motions. In terms of the complexity of slip models, although our analysis is focused on high frequencies, our slip model is at least as simple as conventional low-frequency slip models. Such results would be useful in constructing source models of future great subduction-zone earthquakes for strong-motion prediction.