Observations of remotely triggered seismicity in Salton Sea and Coso geothermal regions, Southern California, USA, after big (M_W>7.8) teleseismic earthquakes
Observations of remotely triggered seismicity in Salton Sea and Coso geothermal regions, Southern California, USA, after big (M_W>7.8) teleseismic earthquakes
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美国南加州索尔顿海和科索地热区远震大地震（M_W>7.8）后远程触发地震活动观测
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发表时间：
2017
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通讯作者：
J. Stock
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作者：
R. Castro;R. Clayton;E. Hauksson;J. Stock
利用重新定位的地震目录，研究了美国南加州索尔顿海和科索地热区大（M_W>7.8）地震期间和之后地震活动率的变化。在这两个地区的地震活动进行了分析，在30天的窗口之前和之后发生的五个大地震：2002年德纳里断层，阿拉斯加（M_W 7.9）; 2004年苏门答腊-安达曼（M_W 9.2）; 2010年智利中部（M_W 8.8）; 2011年日本东北冲（M_W 9.1）;以及2012年苏门答腊岛北方近海（M_W 8.6）地震。
Denali（M_W7.9）地震与Salton海地区地震活动的增强相吻合，表明瞬时触发地震活动可能与Salton海地区面波的传播有关。然而，在科索地区，地震活动率在30天的观测期内基本保持不变。2004年苏门答腊-安达曼（M_W9.2）地震后，两个地区的地震活动在大地震后9天增加。2010年智利（M_W8.8）地震后，两个地区的地震活动在远程事件发生后约14天增加。2011年日本9.1级地震发生后，索尔顿海和科索地区的地震活动分别增加了17天和14天，表明这两个地区的延迟触发地震活动是在面波通过后诱发的。同样，2012年北方苏门答腊（M_W 8.6）地震后6天和16天，索尔顿海和科索地区的地震活动也分别增加。这些观测结果可以被解释为远程大地震引起的瞬时和延迟动态触发的证据。延迟触发震群的最大震级随大震强度（M0/D）的增大而增大，远震越强，延迟时间越长。
A relocated catalog was used to search for changes in seismicity rate in the Salton Sea and the Coso geothermal regions, southern California, USA, during and after large (M_W>7.8) teleseismic earthquakes. Seismicity in these two regions was analyzed within 30- day windows before and after the occurrence of five major earthquakes: the 2002 Denali fault, Alaska (M_W 7.9); the 2004 Sumatra-Andaman (M_W 9.2); the 2010 Central Chile (M_W 8.8); the 2011 Tohoku-Oki, Japan (M_W 9.1); and the 2012 Offshore Northern Sumatra (M_W 8.6) earthquakes.
The Denali (M_W 7.9) earthquake coincided with an increase in seismicity in the Salton Sea region the day when this remote event occurred, indicating that instantaneous triggered seismicity was likely related with the passage of its surface waves. However, in the Coso region the seismicity rate remained approximately constant during the 30-day observation period. The seismicity after the 2004 Sumatra-Andaman (M_W 9.2) earthquake increased in both regions 9 days after the mega-earthquake. The seismicity after the 2010 Chile (M_W 8.8) earthquake increased in both regions approximately 14 days after the remote event. The seismicity in Salton Sea and Coso regions increased 17 and 14 days, respectively, after the 2011 Japan (M_W 9.1) earthquake, suggesting that delayed triggered seismicity was induced after the passage of the surface waves in both regions. Similarly, 6 and 16 days after the 2012 northern Sumatra (M_W 8.6) earthquake the seismicity also increased in Salton Sea and Coso regions, respectively. These observations can be interpreted as evidence of instantaneous and delayed dynamic triggering induced by large remote earthquakes. The maximum magnitude of the delayed triggered swarm increased with the strength (M_0/D) of the mega-earthquake and, the stronger the remote earthquake, the longer the delay time.