2014年新疆于田MS7.3地震的发震构造及余震特征

Seismogenic fault and aftershock characteristics for the 2014 MS7.3 Yutian earthquake,Xinjiang

  • 摘要: 利用2014年10月至2019年9月期间欧空局Sentinel-1卫星采集的合成孔径雷达数据分析了2014年2月12日新疆于田MS7.3地震的震后形变场。结果表明,此次地震造成了南硝尔库勒断裂上明显的震后形变,首次从地震形变场的角度验证了此次地震的发震构造为NE向的左旋走滑断裂,而非部分研究所认为的近NS向断裂。由合成孔径雷达干涉测量得到的多年平均速率图显示主震的西侧仅出现了少量震后余滑且仍为强闭锁区,这意味着2008年和2014年于田两次MS7.3地震之间的区域仍存在发生强震的风险;在2014年主震的东侧,南硝尔库勒断裂和阿什库勒—硝尔库勒断裂呈蠕滑状态,故而余震较少,表明该区域近期发生强震的风险较低。

     

    Abstract: Using synthetic aperture radar (SAR for short) data collected by the European Space Agency’s Sentinel-1 satellites during the period from October 2014 to September 2019, the postseismic deformation following the MS7.3 earthquake in Yutian, Xinjiang on 12 February 2014 was analyzed. The result showed that this earthquake induced obvious postseismic deformation along the southern Xorkol fault. It is for the first time that the seismogenic fault is confirmed to be one northeast-striking left-laterally strike-slip fault in the seismic deformation view, instead of another north-south-trending fault as proposed by a few studies. The InSAR (interferometric SAR) mean velocity map shows that there are only small postseismic slips and the fault is still strongly locked in the west of the main shock, which indicates that the risk of strong earthquake is high in the gap between the 2008 and 2014 Yutian MS7.3 earthquakes. However, in the east of the 2014 main shock, both the southern Xorkol fault and Ashikule-Xorkol fault are creeping with few aftershock activities, suggesting a lower level risk of strong earthquake for this region in the near future.

     

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