A Global Search for Triggered Tremor Following the 2011 Mw 9.0 Tohoku Earthquake
A Global Search for Triggered Tremor Following the 2011 Mw 9.0 Tohoku Earthquake
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DOI：
10.1785/0120120171
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发表时间：
2013-05-01
影响因子：
3
通讯作者：
Matsuzawa, Takanori
中科院分区：
文献类型：
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作者：
Chao, Kevin;Peng, Zhigang;Matsuzawa, Takanori
2011年日本东北地区发生的里氏9.0级地震在全球多地引发了深部构造震动和浅层微地震。在这里，我们对先前已识别出环境或触发震颤的区域的触发震颤进行了系统调查。阿拉斯加中南部、阿留申群岛弧、日本西南部的四国、新西兰北岛、俄勒冈州南部、加利福尼亚州中部圣安德烈亚斯断层的帕克菲尔德-乔拉姆段、加利福尼亚州南部的圣哈辛托断层、台湾和温哥华岛等地区引发了地震。我们没有发现加利福尼亚州北部卡拉维拉斯断层引发地震的证据。控制触发电位的最重要因素之一是表面波的幅度。本研究检查的数据表明，触发震颤的阈值幅度类似于 0.1 厘米/秒，相当于类似于 10 千帕的动态应力阈值。远震面波的入射角也会影响洛夫波和瑞利波的触发势。这项研究的结果证实，洛夫波和瑞利波都有助于引发许多区域的震颤。在已知发生环境震颤和触发震颤的地区，东北事件触发的震颤通常发生在与先前识别的环境震颤和/或触发震颤相似的位置，这进一步支持了这样的观点：尽管触发震颤和环境震颤的驱动力不同，但它们具有相似的机制。我们发现触发波的幅度与触发震颤的幅度之间存在正相关关系，这与时钟提前模型的预测一致。
The 2011 M-w 9.0 Tohoku, Japan, earthquake triggered deep tectonic tremor and shallow microearthquakes in numerous places worldwide. Here, we conduct a systematic survey of triggered tremor in regions where ambient or triggered tremor has been previously identified. Tremor was triggered in the following regions: south-central Alaska, the Aleutian Arc, Shikoku in southwest Japan, the North Island of New Zealand, southern Oregon, the Parkfield-Cholame section of the San Andreas fault in central California, the San Jacinto fault in southern California, Taiwan, and Vancouver Island. We find no evidence of triggered tremor in the Calaveras fault in northern California. One of the most important factors in controlling the triggering potential is the amplitude of the surface waves. Data examined in this study suggest that the threshold amplitude for triggering tremor is similar to 0.1 cm/s, which is equivalent to a dynamic stress threshold of similar to 10 kilopascals. The incidence angles of the teleseismic surface waves also affect the triggering potentials of Love and Rayleigh waves. The results of this study confirm that both Love and Rayleigh waves contribute to triggering tremor in many regions. In regions where both ambient and triggered tremor are known to occur, tremor triggered by the Tohoku event generally occurred at similar locations with previously identified ambient and/or triggered tremor, further supporting the notion that although the driving forces of triggered and ambient tremor differ, they share similar mechanisms. We find a positive relationship between the amplitudes of the triggering waves and those of the triggered tremor, which is consistent with the prediction of the clock-advance model.