Identification of Paleoearthquakes and Coseismic Slips on a Normal Fault Using High-Precision Quantitative Morphology: Application to the Jiaocheng Fault in the Shanxi Rift, China
Identification of Paleoearthquakes and Coseismic Slips on a Normal Fault Using High-Precision Quantitative Morphology: Application to the Jiaocheng Fault in the Shanxi Rift, China
复制标题
利用高精度定量形态学识别正断层上的古地震和同震滑动：在中国山西裂谷交城断层中的应用
DOI：
10.2113/2021/2550879
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发表时间：
2021
期刊：
影响因子：
2.4
通讯作者：
Shuang Geng
中科院分区：
文献类型：
--
作者：
Junjie Zou;Honglin He;Yusuke Yokoyama;Adam D. Sproson;Yoshiki Shirahama;Yongsheng Zhou;Zhanyu Wei;Feng Shi;Shuang Geng
抽象的。基岩断层面的定量形态学与航空测量和野外鉴定相结合，是在传统探槽方法不适用的基岩地区识别古地震、获取同震滑动和评价活动断层孕震能力的有效方法。在这里，我们报告了山西裂谷交城断裂（JCF）的案例研究，中国。虽然对JCF进行了一些研究，但其同震滑动历史和孕震能力仍然不清楚。为了解决这些问题，我们调查了两个基岩断层面，四西村（SXC）和上兰镇（SLZ），在JCF的北方段，使用定量形态分析与航空和实地调查。基于各向同性经验变差函数和移动窗的定量分形分析表明，两个基岩断层面都具有垂直分段的特征，这可能是周期性地震的结果，其同震滑动可由分段高度确定。三个地震事件在SXC，同震垂直滑动1.74，1.65，和1.99米，和三个地震事件在SLZ，同震垂直滑动1.32，2.35，和1.88米，被确定。与以往的研究相比，这三次地震事件可能发生在全新世，但需要绝对测年年龄来支持，这也是我们今后工作的重点。考虑到地震能力（M>7.5）和~2.6 kyr的复发间隔与超过3 kyr的流逝时间之间的关系，JCF的北方和中段的地震危险性需要立即关注。
Abstract. The quantitative morphology of bedrock fault surfaces combined with aerial surveys and field identification is a useful approach to identify paleoearthquakes, obtain coseismic slips, and evaluate the seismogenic capacity of active faults in bedrock areas where traditional trenching methods are not applicable. Here, we report a case study of the Jiaocheng Fault (JCF) in the Shanxi Rift, China. Although several studies have been conducted on the JCF, its coseismic slip history and seismogenic capacity are still unclear. To address these problems, we investigated two bedrock fault surfaces, Sixicun (SXC) and Shanglanzhen (SLZ), on the JCF’s northern segment using quantitative morphological analysis together with aerial and field surveys. Quantitative fractal analysis based on the isotropic empirical variogram and moving window shows that both bedrock fault surfaces have the characteristics of vertical segmentation, which is likely due to periodic earthquakes, the coseismic slip of which can be determined by the height of the segments. Three seismic events at SXC, with a coseismic vertical slip of 1.74, 1.65, and 1.99 m, and three seismic events at SLZ, with a coseismic vertical slip of 1.32, 2.35, and 1.88 m, are identified. Compared with the previous studies, these three seismic events may occur in the Holocene, but it requires absolute dating ages to support, which is also the focus of our future work. Considering the seismologic capability (M>7.5) and the relationship between the recurrence interval of ~2.6 kyr and elapsed time of more than 3 kyr, the seismic hazard of the northern and middle segments of the JCF requires immediate attention.