Figure 1. Tectonic setting of Turkey. The majority of Turkey is on the Anatolian block at the plate boundary zone of the Eurasian, Arabian, and African plates. Tectonic activities are mainly controlled by the right-lateral strike-slip North Anatolian fault and the left-lateral strike-slip East Anatolian fault. GPS velocities relative to a fixed Eurasian plate (Blewitt et al., 2018) show counter-clockwise rotational movement of the Anatolian block, and the Arabian plate moving north. Most of the representative focal mechanism solutions since 1990 (U.S. Geological Survey Earthquake Hazards Program, 2017) are crustal deformations with strike-slips or extensional slips. Earthquakes since Feb 06, 2023 are clustered around the East Anatolian fault zone. 图一：土耳其的构造背景。土耳其大部分处在欧亚-阿拉伯-非洲板块交界处的安纳托利亚地块上，构造运动主要受右行走滑北安纳托利亚断层和左行走滑东安纳托利亚断层的控制。相对于固定的欧亚板块的GPS速度（Blewitt et al., 2018）显示安纳托利亚地块正进行逆时针旋转，而阿拉伯板块正在向北运动。1990年以来代表性的震源机制（USGS地震灾害项目组，2017）主要是地壳走滑、伸展地震。2023年2月6日以来的地震集中在东安纳托利亚断层带一代。 Figure 2. GPS coseismic displacement of the two large earthquakes (Blewitt et al., 2018) show left-lateral strike-slips, with the deformations being more NE-SW for the Mw 7.75 (blue arrows) along the East Anatolian fault and more E-W for the Mw 7.55 (red arrows) along the Cardak fault. Focal mechanisms (U.S. Geological Survey Earthquake Hazards Program, 2017) show left-lateral strike-slip along the aforementioned faults as well as E-W extensions along the Savrun and the Dead Sea faults. Despite the appearance of the Mw 7.75 hypocenter near the Dead Sea fault zone, InSAR data from the ALOS-2 satellite (Geospatial Information Authority of Japan, 2023) show that the Mw 7.75 actually ruptured the East Anatolian fault with more than 5 meters of slip. Black double opposing arrows show the maximum horizontal stress compiled from the world stress map (Heidbach et al., 2016) in N-S to NNE-SSW directions near the faults, consistent with the left-lateral strike-slip and E-W extensions. 图二：GPS同震形变(Blewitt et al., 2018)显示7.75级地震沿东安纳托利亚断层的东北-西南向左行走滑和7.55级地震沿Cardak断层的东西向左行走滑。震源机制(USGS地震灾害项目组，2017)也显示沿前述断层的左行走滑，以及沿Savrun断层和死海断层的东西向伸展形变。尽管7.75级地震的震中显示在死海断层附近，ALOS-2卫星的InSAR数据(日本空间信息局，2023)显示此次7.75级地震实际上破裂的是东安纳托利亚断层并造成超过5米的位移。相对的黑色箭头显示编译于世界应力地图的最大水平应力(Heidbach et al., 2016)为南北向或北北东-南南西方向，也与左行走滑和东西向伸展一致。 Figure 3. Scaled sum of the shake intensities (with a 5% increase for the Mw 7.55) and population density by province in the most affected areas in Turkey and Syria. Denser and darker colors show that Gaziantep and Hatay provinces are probably the most affected areas with high population. 图三：两次地震的烈度之和（给7.55级地震赋予了5%的增益）与土耳其叙利亚两国的分省人口密度。更深更暗的颜色显示Gaziantep和Hatay两省可能是受地震影响最大而人口密集的省份。 Figure 4. InSAR coseismic displacements of the Turkey earthquakes on 02/06/2023 from ALOS-2 satellite, from Geospatial Information Authority of Japan (2023). 图四：2023年2月6日土耳其地震的ALOS-2卫星InSAR同震形变，来自日本空间信息局（2023）。
Blewitt, G., Hammond, W.C., and Kreemer, C., 2018, Harnessing the GPS Data Explosion for Interdisciplinary Science: Eos, v. 99, doi:10.1029/2018EO104623.
Geospatial Information Authority of Japan, 2023, The 2023 Turkey earthquake: crustal deformation detected by ALOS-2 data:, https://www.gsi.go.jp/cais/topic20230206-e_Turkey.html.
Heidbach, O., Rajabi, M., Reiter, K., Ziegler, M., and Team, W., 2016, World Stress Map Database Release 2016: GFZ Data Services, doi:10.5880/WSM.2016.001.
U.S. Geological Survey Earthquake Hazards Program, 2017, Advanced National Seismic System (ANSS) Comprehensive Catalog of Earthquake Events and Products:, doi:10.5066/F7MS3QZH.
