SUMMARY

We analysed coseismic surface displacements of the 2020 January 24 Elazığ (M 6.75) Earthquake using GPS (Global Positioning System) measurements to investigate the associated fault slip distribution and static stress change. Our geodetic analysis of 13 GPS sites surrounding the epicentre included data from four additional sites. We accurately located the nucleation point of the main shock at 38.310° N, 39.081° E (±1.4 km) and at a depth of 5.2 ± 1.2 km. Both seismograph and GPS-derived fault plane solutions confirmed that it has a nearly pure sinistral mechanism with a negligible obliquity. The main shock generated 29.2 cm average sinistral slip along an approximately 70 km long and 20 km wide section of the East Anatolian Fault. Based on its rupture size and average slip, its magnitude was found to be M_w 6.75. An average of 6.6 bars of stress drop occurred on the rupture plane. The rupture occurred bilaterally failing two separate segments both to the northeast and to the southwest of the nucleation point. Average sinistral slips were 14.6 and 47.4 cm along the southwestern and northeastern segments, respectively. Sinistral slip reached up to 53.1 cm along the southwestern segment and 110.5 cm along the northeastern segment. During the generation process of the 2020 earthquake, 78 per cent of the slip deficit had been released aseismically since 1875. Increasing Coulomb stress by an average of 2.5 bars, it substantially increased earthquake hazard on the 1874 (M 7.1) rupture zone, which might have already accumulated 1.51 m slip deficit on its fully locked patches. Furthermore, increasing Coulomb stress by an average of 0.5 bars, it raised earthquake hazard on the 1893 (M 7.1) rupture zone, which might have already stored 1.01 m slip deficit along the fully locked patches.

中文翻译：

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2020年Elazığ地震（Mw 6.75）的滑动分布及其对安纳托利亚东部地震灾害的影响

概要

我们使用GPS（全球定位系统）测量结果分析了2020年1月24日Elazığ（M 6.75）地震的同震表面位移，以调查相关的断层滑动分布和静应力变化。我们对震中周围13个GPS站点的大地分析包括来自另外四个站点的数据。我们将主震的成核点准确定位在38.310°N，39.081°E（±1.4 km）和5.2±1.2 km深度处。地震仪和GPS衍生的断层平面解都证实了它具有几乎纯净的正弦机制，而倾角可忽略不计。主震沿东安纳托利亚断层约70公里长，20公里宽的部分平均产生29.2 cm的左旋滑移。根据其破裂尺寸和平均滑动，发现其大小为中号_W¯¯ 6.75。断裂面上平均出现6.6巴的应力下降。破裂发生在双侧，使成核点的东北和西南两个独立的部分破裂。西南段和东北段的平均鼻窦滑移分别为14.6和47.4 cm。沿西南段的正滑移达到53.1 cm，而沿东北段的滑移达到110.5 cm。在2020年地震的发生过程中，自1875年以来，已经通过抗震释放了78％的滑移赤字。库仑应力平均增加2.5巴，在1874年大幅度增加了地震危险（M7.1）破裂带，该破裂带可能已经在其完全锁定的斑块上积累了1.51 m的滑差。此外，库仑应力平均增加0.5 bar，在1893（M 7.1）破裂带上增加了地震危险，该破裂带可能已经在完全锁定的斑块上储存了1.01 m的滑移赤字。