张克亮^1,,
甘卫军^1,,,
梁诗明¹,
肖根如²,
代成龙¹,
王阅兵^1,3,
李长军^1,4,
张玲¹,
马广庆⁵
1. 中国地震局地质研究所 地震动力学国家重点实验室, 北京 100029
2. 东华理工大学 测绘工程学院, 南昌 330013
3. 中国地震台网中心, 北京 100045
4. 中国地震第二监测中心, 西安 710054
5. 河北省地震局河北地震台, 石家庄 050021

基金项目: 国家重点研发计划项目（2018YFC1503300和2019YFE0108900）资助


详细信息

作者简介: 张克亮, 男, 1981年生, 副研究员, 主要从事GNSS地壳形变特征及动力学机制研究.E-mail:klzhang@ies.ac.cn

通讯作者: 甘卫军, 男, 1964年生, 研究员, 主要从事GNSS大地测量与地壳形变研究.E-mail:wjgan@ies.ac.cn

中图分类号: P223;P313

收稿日期:2021-06-11
修回日期:2021-06-16
上线日期:2021-07-10

Coseismic displacement and slip distribution of the 2021 May 21, M_S6.4, Yangbi Earthquake derived from GNSS observations

ZHANG KeLiang^1,,
GAN WeiJun^1,,,
LIANG ShiMing¹,
XIAO GenRu²,
DAI ChengLong¹,
WANG YueBing^1,3,
LI ZhangJun^1,4,
ZHANG Ling¹,
MA GuangQing⁵
1. State Key Laboratory of Earthquake Dynamics, Institute of Geology, China Earthquake Administration, Beijing 100029, China
2. Faculty of Geomatics, East China University of Technology, Nanchang 330013, China
3. China Earthquake Network Center, Beijing 100045, China
4. The Second Monitoring and Application Center, Xi'an 710054, China
5. Hebei Earthquake Agency, Shijiazhuang 050021, China


More Information

Corresponding author: GAN WeiJun,E-mail:wjgan@ies.ac.cn

MSC: P223;P313

--> Received Date: 11 June 2021
Revised Date: 16 June 2021
Available Online: 10 July 2021


摘要
摘要:2021年5月21日云南大理州漾濞县发生了M_S6.4强震.地震未产生明显的地表破裂，但前震-主震-余震大致呈线状展布于维西—乔后—巍山断裂的西南侧.我们基于覆盖震中区域的高密度连续GNSS观测台阵，观测获得了震区周围50 km范围的高精度、高密度三维同震形变场.结果显示：地震破裂为明显的右旋走滑兼拉张；地表形变场呈现出走滑断裂前端压缩隆升、尾端拉张下沉的典型变形模式；GNSS观测到最大水平位移和垂直下沉分别达46 mm（漾濞县淮安村周围）和-44 mm（漾濞县秀岭林场周围）；发震断裂的地表错动从漾濞淮安村GNSS观测站和秀岭林场GNSS观测站之间的狭小地带穿过.在此基础上，我们以前震和主震精定位结果为约束，推测发震断层面走向135°、倾向SW、倾角80°，进而通过弹性半空间断裂位错模型，对发震断层面的同震滑动分布进行了反演.初步反演结果表明：同震滑动主要集中分布在3~12 km深度范围内，矩震级为M_W6.04，滑动量分布与前震序列呈现较好的空间一致性.
关键词: 漾濞M_S6.4地震/
GNSS观测/
同震形变/
破裂滑动分布

Abstract:The Yangbi M_S6.4 Earthquake occurred on May 21, 2021 in Dali, Yunnan Province of China. While it does not produce clear surface ruptures, the earthquake sequence of foreshocks, mainshock and aftershocks distributes linearly to the southwest of the Weixi-Qiaohou-Weishan fault. Based on the observations of a dense GNSS observation network covering the earthquake, we obtained 3-D coseismic displacements in the area within the scope of 50 km from the epicenter. The results show that:a) the earthquake surface rupture is characterized by dextral slip with extension movement; b) the maximum horizontal and vertical displacements are 46 mm (near Huai'an village, Yangbi county) and -44 mm (near Xiuling farm, Yanbi county), respectively; c) coseismic displacement field shows uplift under compression at the fore tips and subsidence due to extension at the end tips of the seismogenic fault, a typical deformation pattern associated with lateral-slip faulting; d) The surface of the seismogenic fault passes through the narrow area between the GNSS stations of Huai'an Village and Xiuling Farm, Yangbi county. Based on the characteristics of coseismic displacements, the spatial distribution of foreshocks and mainshock and the active faults, we inferred the preferred geometric parameters of seismogenic fault with a strike angle of 135°, SW-trending, and a dip angle of 80°. We further estimated the coseismic slip distribution with the constraint from the coseismic displacements in terms of elastic half-space dislocation model. The preliminary results show that the coseismic slips are mainly distributed at the depths between 3 to 12 km with the mean slip of 236 mm, and the moment magnitude of M_W6.04; the coseismic slip is spatially coherent with the foreshocks.
Key words:The M_S6.4 Yangbi Earthquake/
GNSS observations/
Coseismic displacement/
Coseismic slip distribution



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