Complementary Occurrence of Fault Creep and an MW 6.5 Earthquake Along the Philippine Fault on Leyte Island Revealed by ALOS and ALOS-2 Sar Interferometry
Complementary Occurrence of Fault Creep and an MW 6.5 Earthquake Along the Philippine Fault on Leyte Island Revealed by ALOS and ALOS-2 Sar Interferometry
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DOI：
10.1109/igarss.2019.8898729
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发表时间：
2019-07
期刊：
影响因子：
--
通讯作者：
Y. Fukushima;M. Hashimoto
中科院分区：
文献类型：
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作者：
Y. Fukushima;M. Hashimoto
据推测，菲律宾在莱特岛的断层一直在爬行。2017年7月6日，莱特岛北部发生6.5兆赫地震，表明并不是断层上的所有部分都在蠕动。我们利用ALOS/PALSAR数据(2006-2011年)进行了InSAR时间序列分析，以估计断层蠕变速率的空间变化，并利用ALOS-2/PALSAR-2干涉测量获得的位移对2017年地震进行了断层滑动模拟。我们发现，2017年地震破裂的地段已经被锁定(没有断层蠕动)，而邻近的地段，在岛的最北端和中部地区，已经以高达30毫米/年的速度爬行。我们从蠕变分析中推测，2017年的地震规模将是莱特岛北半部菲律宾断层沿线发生的最大级别地震。考虑到大小和位置上的相似性，我们推断1947年的地震也破裂了与2017年地震相同的锁定部分。我们的发现证明了InSAR时间序列分析在识别活动断裂沿线未来地震易发区的有效性。
It has been inferred that the Philippine fault on Leyte Island has been creeping. On 6 July 2017, an Mw 6.5 earthquake struck northern Leyte, suggesting that not all parts along the fault have been creeping. We conducted InSAR time-series analyses using ALOS/PALSAR data (2006-2011) to estimate the spatial variation of the fault creep rate, and fault slip modeling of the 2017 earthquake using the displacements obtained from ALOS-2/PALSAR-2 interferometry. We found that the section ruptured by the 2017 earthquake had been locked (lack of fault creep) while the neighboring sections, in northernmost and central areas of the island, have been creeping with rates of up to 30 mm/year. We speculate from the creep analysis that the size of the 2017 earthquake would be the maximum-class earthquake along the Philippine fault in the northern half of Leyte. Considering the similarity in size and location, we infer that the 1947 earthquake also ruptured the same locked portion as the 2017 earthquake. Our findings demonstrate the usefulness of InSAR time-series analysis to identify future earthquake-prone sections along active faults.