测绘学报 ›› 2019, Vol. 48 ›› Issue (10): 1244-1253.doi: 10.11947/j.AGCS.2019.20180587

• 大地测量学与导航 • 上一篇    下一篇

利用InSAR和GPS数据分析台湾西南两次Mw>6地震的触发关系及应力影响

王乐洋1, 高华1,2, 冯光财3   

  1. 1. 东华理工大学测绘工程学院, 江西 南昌 330013;
    2. 武汉大学测绘遥感信息工程国家重点实验室, 湖北 武汉 430079;
    3. 中南大学地球科学与信息物理工程学院, 湖南 长沙 410083
  • 收稿日期:2018-12-20 修回日期:2019-07-10 出版日期:2019-10-20 发布日期:2019-10-24
  • 通讯作者: 高华 E-mail:gaohuastudent@163.com
  • 作者简介:王乐洋(1983-),男,博士,教授,研究方向为大地测量反演及大地测量数据处理。E-mail:wleyang@163.com
  • 基金资助:
    国家自然科学基金(41664001;41874001);江西省杰出青年人才资助计划(20162BCB23050);国家重点研发计划(2016YFB0501405)

Triggering relations and stress effects analysis of two Mw>6 earthquakes in southwest Taiwan based on InSAR and GPS data

WANG Leyang1, GAO Hua1,2, FENG Guangcai3   

  1. 1. Faculty of Geomatics, East China University of Technology, Nanchang 330013, China;
    2. State Key Laboratory of Information Engineering in Surveying, Mapping and Remote Sensing, Wuhan University, Wuhan 430079, China;
    3. School of Geoscience and Info-Physics Engineering, Central South University, Changsha 410083, China
  • Received:2018-12-20 Revised:2019-07-10 Online:2019-10-20 Published:2019-10-24
  • Supported by:
    The National Natural Science Foundation of China (Nos. 41664001;41874001);The Support Program for Outstanding Youth Talents in Jiangxi Province (No. 20162BCB23050);The National Key Research and Development Program (No. 2016YFB0501405)

摘要: 利用InSAR和GPS进行地震研究具有很大的优势,InSAR能够在较大范围内快速地获得连续的同震形变观测,而GPS测量精度高,可迅速获得稳定的测量结果。随着SAR卫星的增多、重返周期的缩短,利用InSAR和GPS联合进行地震触发关系及应力影响研究也变得更为有力。2010年3月4日和2016年2月6日台湾西南部接连发生两次Mw 6.0以上地震,分别被称为甲仙地震和美浓地震。本文利用GPS和InSAR同震形变场联合反演了甲仙地震的滑动分布模型;结合之前的研究成果,基于静态库伦应力改变对甲仙地震与美浓地震的关系进行了分析;还为台湾西南部7个主要断层构建了断层格网并获取了它们的应力改变模型。结果表明,甲仙地震的发震断层表现为逆冲倾滑兼一定走滑分量的断层。甲仙地震的主要滑动区域处于12~16 km深度之间;最大滑动量为0.61 m位于约14 km深处。本文线性反演得到的甲仙地震地震矩为2.27×1018 Nm,相当于Mw 6.20。甲仙地震后美浓地震的发震断层上应力增值达4.0 MPa,应力增加的面积约占推断断层总面积的74%,表明甲仙地震对美浓地震的发生具有十分明显地加速作用。甲仙和美浓地震共同作用下,西侧的左镇断层和新化断层产生了较明显地应力积累。根据应力改变结果,本文认为甲仙地震和美浓地震后,台湾西南部的左镇断层和新化断层都具有较高的危险性,值得持续关注和进一步研究。

关键词: 甲仙地震, 震源参数反演, InSAR, 地震触发, 静态库伦应力

Abstract: InSAR and GPS have great advantages in seismic research. InSAR can quickly obtain continuous co-seismic deformation observation in a wide range, while GPS has high accuracy and can quickly obtain stable measurement. With the increase of SAR satellites and the shortening of the return period, it is more powerful to study the seismic triggering relationship and stress effects by using InSAR and GPS jointly. On March 4, 2010, and February 6, 2016, two earthquakes with Mw>6.0 occurred successively in southwestern Taiwan, which are called Jiashian earthquake and Meinong earthquake, respectively. Those are two of the three destructive earthquakes that have occurred in the southwestern plain of Taiwan in the last 200 years (the other was the 1946 M 6.1 Hsinhua earthquake). The time and space intervals between Jiashian and Meinong earthquakes are very small. The study of the relationship between them can not only explore the underground structure of the two events but also further understand the triggering relationship between strong earthquakes. In addition, the effect of the surrounding faults after the two events and which faults have high seismic risk are also worth discussing. As no scholar has deeply studied the relationship between the two events and the effect of the surrounding faults, we used the GPS and InSAR coseismic deformation obtained from ALOS to invert the slip distribution model of the Jiashian earthquake. Based on the static Coulomb stress model, the relationship between Jiashian and Meinong earthquake is analyzed. Seven faults in southwestern Taiwan have been constructed and the stress change models of them have been obtained. We analyzed the high earthquake risk area in southwestern Taiwan based on these stress change models. Fault model obtained by InSAR and GPS inversion shows that the fault structures of Jiashian and Meinong events are very similar, both of which are thrust faults with certain strike-slip. The major slip area of the Jiashian event is between 12~16 km which is slightly deep than that of the Meinong event. The maximum slip of the Jiashian event is 0.61 m at about 14 km depth. The moment of the Jiashian event we obtained by linear inversion is 2.27×1018 Nm corresponding to Mw 6.20 which is consistent with the results of USGS (Mw 6.21) and GCMT (Mw 6.3). After Jiashian earthquake, the stress on the causative fault of Meinong event increased greatly, the maximum increment reached 4.0 MPa, and the area of stress increase accounted for about 74% of the total area of the inferred fault. This shows that the Jiashian earthquake has a very obvious acceleration effect on the Meinong earthquake. However, after the Meinong event, the stress of the causative fault of the Jiashian event increased less, and the average increment is only 0.03 MPa. Under the combined effect of the Jiashian and Meinong events, the Zouchen and Hsinhua faults on the west of the Jiashian earthquake have obviously stress accumulated. We believe that Zuochen and Hsinhua faults in southwestern Taiwan are of high risk after Jiashian and Meinong earthquakes, which deserve continuous attention and further study.

Key words: the Jiashian earthquake, inversion of seismic source parameters, InSAR, earthquake triggering, static Coulomb stress

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