王向腾^1,2,3,,
倪四道^2,,,
周勇⁴,
林鑫²
1. 东华理工大学核资源与环境国家重点实验室, 南昌 330013
2. 中国科学院测量与地球物理研究所大地测量与地球动力学国家重点实验室, 武汉 430077
3. 中国科学院大学, 北京 100049
4. 南方科技大学, 深圳 518055

基金项目: 国家自然科学基金（41874068，41904044），核资源与环境国家重点实验室开放基金（NRE1920）联合资助


详细信息

作者简介: 王向腾, 男, 讲师, 主要从事地震定位与震源参数研究.E-mail:wangxt@whigg.ac.cn

通讯作者: 倪四道, 男, 研究员, 主要从事地震学研究.E-mail:sdni@whigg.ac.cn

中图分类号: P315

收稿日期:2018-07-31
修回日期:2019-01-15
上线日期:2019-12-05

Topography effects for focal depth inversion of shallow earthquakes based on waveforms: A case study for the M6.3 event on 3 September 2017 in Democratic People's Republic of Korea

WANG XiangTeng^1,2,3,,
NI SiDao^2,,,
ZHOU Yong⁴,
LIN Xin²
1. State Key Laboratory of Nuclear Resources and Environment, East China University of Technology, Nanchang 330013, China
2. State Key Laboratory of Geodesy and Earth's Dynamics, Institute of Geodesy and Geophysics, Chinese Academy of Sciences, Wuhan 430077, China
3. University of Chinese Academy of Sciences, Beijing 100049, China
4. Southern University of Science and Technology, Shenzhen 518055, China


More Information

Corresponding author: NI SiDao,E-mail:sdni@whigg.ac.cn

MSC: P315

--> Received Date: 31 July 2018
Revised Date: 15 January 2019
Available Online: 05 December 2019


摘要
摘要:震源深度是核试验以及塌陷等浅源地震研究中的关键参数，可以为事件成因分析提供关键信息.然而朝鲜核试验区域地形起伏较大，地形效应可能对震源深度反演的结果造成影响.本文基于理论地震图进行测试，研究了地形起伏对震源深度反演的影响.发现震源深度小于2 km时，不考虑地形影响，反演得到的震源深度会系统偏浅0.2 km左右.然后利用MDJ2速度结构模型，我们反演了2017年9月3日朝鲜M6.3事件的震源参数，结果显示震源深度约为0.8 km.进一步基于带地形的格林函数重新反演了该事件的震源深度，发现在1 km处波形拟合结果较好.不同速度模型测试结果显示该事件的震源深度反演误差约为1 km.案例研究表明，基于层状均匀速度模型，利用区域地震波形资料反演的震源深度可以为浅源事件成因分析提供关键约束.
关键词: 浅源地震/
地形起伏/
震源深度/
波形反演

Abstract:Focal depth is an important parameter for analyzing causes of shallow earthquakes,such as nuclear test and collapse earthquakes. However,for very shallow earthquakes in the region of larger relief,the effects of topography for focal depth inversion based on regional seismic may not be ignored. In this study,the topographic effects are tested based on synthetic waveforms. For the shallow earthquakes with focal depth less than 2 km,the inverted focal depths based on layer velocity models are smaller than the input parameters,about 0.2 km. Based on the widely used MDJ2 crust model in the study region,we inverted the source parameters of the M6.3 event on 3 September 2017 in Democratic People's Republic of Korea,the focal depth is about 0.8 km. In order to study the effects of topography,we also calculate the Green's functions based on the MDJ2 crustal model with the topography in the study region. The result indicates that the focal depth is about 1 km. The test results of based on 10% perturbations of MDJ2 velocity model in the shallow crust show that the uncertainty of the focal depth inversion is about 1 km. The case study indicates that the focal depth inverted by regional seismic waveforms based on the flat velocity model can also provide a crucial constraint for analyzing the causes of shallow earthquakes.
Key words:Shallow earthquakes/
Topographic relief/
Focal depth/
Waveform inversion



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