Seismic moment release before the May 12, 2008, Wenchuan earthquake in Sichuan of southwest China
Seismic moment release before the May 12, 2008, Wenchuan earthquake in Sichuan of southwest China
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DOI：
10.1002/cpe.1522
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发表时间：
2010
期刊：
影响因子：
--
通讯作者：
Changsheng Jiang;Zhongliang Wu
中科院分区：
文献类型：
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作者：
Changsheng Jiang;Zhongliang Wu
大震前地震矩释放是加速还是平静是地震中期预报或地震时变危险性研究中有争议的问题之一。2008年5月12日汶川地震提供了一个独特的机会，以检查是否加速时刻释放（AMR）或平静存在之前，这场大地震。为了系统分析这一巨大内陆逆冲事件的地震矩释放，结合这一事件的特殊性，利用当地截止震级为ML3.0的地震目录，采取了4种升级方法。我们提出了一个BIC标准作为曲率参数q的发展，以确定统计上显着的加速或静止行为相比，线性增加。我们使用“日食法”作为“干扰事件考虑”的发展，以消除附近地震活动断裂带的干扰。我们考虑m系数在（T，R，Mc）空间的分布，探讨矩释放行为随时间窗口长度T和以核化点为中心的空间窗口半径R以及所用星表的截止星等Mc的变化。我们不仅使用圆形窗，而且还使用“裂缝状”窗来研究与汶川地震相关的力矩释放的整体行为。通过对汶川地震的回顾性实例研究，发现汶川地震前的矩释放在不同的时空范围内确实表现出加速矩释放（AMR）和平静行为，对参数变化具有一定的鲁棒性，反映了此次大地震的孕育过程。然而，对于这次地震，约束故障时间的前向预测模式被证明是困难的。版权所有© 2009约翰威利父子有限公司。
Whether seismic moment release before great earthquakes exhibits accelerating or quiescence behavior is one of the controversial topics in the study of intermediate‐term earthquake forecast or time‐dependent seismic hazard. The May 12, 2008, Wenchuan earthquake provides a unique opportunity to check whether accelerating moment release (AMR) or quiescence existed before this great earthquake. To systematically analyze the precursory moment release, considering the special characteristics of this great inland thrust event, we took four upgraded approaches using the local earthquake catalogue with cutoff magnitude ML3.0. We propose a BIC criterion as a development of the curvature parameter q to identify the statistically significant acceleration or quiescence behavior as compared with linear increase. We use an ‘eclipse method’ as a development of the ‘interfering event consideration’ to eliminate the interference from the nearby seismically active fault zones. We consider the distribution of m‐coefficient in the (T, R, Mc) space, to explore the variation of moment release behavior with temporal window length T and spatial window radius R centered at the nucleation point, and cutoff magnitude Mc of the catalogue in use. We use not only circular windows but also ‘crack‐like’ windows to investigate the overall behavior of the moment release associated with the Wenchuan earthquake. Through this retrospective case study, it is observed that moment release before the Wenchuan earthquake did show accelerating moment release (AMR) and quiescence behavior for different spatio‐temporal ranges, with robustness to some extent against the changing of parameters, indicating the preparation process of this great earthquake. However, for this earthquake, to constrain the failure time in a forward forecasting mode is shown to be difficult. Copyright © 2009 John Wiley & Sons, Ltd.