Deep low‐frequency earthquakes beneath the focal region of the Mw 6.7 2000 Western Tottori earthquake
Deep low‐frequency earthquakes beneath the focal region of the Mw 6.7 2000 Western Tottori earthquake
复制标题
2000 年鸟取县西部 6.7 级地震震源区下方的深层低频地震
DOI：
--
复制
发表时间：
2002
期刊：
影响因子：
--
通讯作者：
K. Obara
中科院分区：
文献类型：
--
作者：
S. Ohmi;K. Obara
2000年10月6日，日本西南部鸟取县西部发生6.7级地震。在震源区下方，在约30千米深处观测到了深层次的低频地震。主震前3年内共检测到5次DLF地震，主震后13个月内共观测到60余次DLF地震。本文利用S波与P波的振幅比和S波的偏振图，研究了主震前9小时大震的震源机制。这两种分析都表明，单力源机制比双力源机制更可取，双力源机制暗示了水或岩浆等流体的输送。这次地震可能是发生在活动断裂带之下的DLF地震的另一个例子。
On October 6, 2000, an Mw = 6.7 crustal earthquake occurred in western Tottori prefecture, southwest Japan. Beneath the focal region of the earthquake, deep low‐frequency (DLF) earthquakes were observed at depths of around 30 km. Five DLF earthquakes were detected within 3 years before the mainshock and more than 60 DLF earthquakes were observed during the 13 months after the mainshock. We investigated the focal mechanism of the DLF earthquake that occurred 9 hours before the mainshock, using amplitude ratios of the S‐waves to the P‐waves and polarization patterns of the S‐waves. Both analyses indicated that a single‐force source mechanism is more preferable than a double‐couple source mechanism, which suggests the transport of fluid such as water or magma. This event is probably another example of DLF earthquakes that occur beneath active fault zones.