肖万博^1,,
陈彦阳²,
王彦宾^1,,,
张元生³
1. 北京大学地球与空间科学学院地球物理系, 北京 100871
2. 中国石油化工股份有限公司石油勘探开发研究院, 北京 100083
3. 中国地震局兰州地震研究所, 兰州 730000

基金项目: 国家自然科学基金项目(41674052)资助


详细信息

作者简介: 肖万博, 男, 汉族, 1997年生, 博士研究生, 主要从事计算地震学研究.E-mail:wbxiao@pku.edu.cn

通讯作者: 王彦宾, 男, 教授, 2000年获日本九州大学博士学位, 主要从事计算地震学研究和地震反演方面的教学和研究工作.E-mail:ybwang@pku.edu.cn

中图分类号: P315

收稿日期:2019-10-15
修回日期:2019-12-22
上线日期:2020-05-05

Regional seismic wave propagation modeling and ground motion characteristics of the 2013 M_S6.6 Minxian Earthquake in Gansu

XIAO WanBo^1,,
CHEN YanYang²,
WANG YanBin^1,,,
ZHANG YuanSheng³
1. Department of Geophysics, School of Earth and Space Sciences, Peking University, Beijing 100871, China
2. Sinopec Petroleum Exploration and Production Research Institute, Beijing 100083, China
3. Lanzhou Institute of Seismology, China Earthquake Administration, Lanzhou 730000, China


More Information

Corresponding author: WANG YanBin,E-mail:ybwang@pku.edu.cn

MSC: P315

--> Received Date: 15 October 2019
Revised Date: 22 December 2019
Available Online: 05 May 2020


摘要
摘要:2013年7月22日，甘肃省定西市岷县发生M_S6.6地震，造成了严重的人员伤亡和经济损失.地震发生于青藏高原东北部边缘与甘肃东南部地区的交界处，是该区域一百多年以来发生的最大地震.分析本次地震观测数据显示，岷县M_S6.6地震产生的地震地面运动呈现出明显的区域变化特征.为了研究这种区域变化特征，本文使用全球CRUST1.0和SRTM30模型数据建立了甘肃岷县及周边地区的地下三维传播介质模型，使用并行的三维有限差分方法进行了岷县地震的区域地震波传播模拟，并与研究区内数字地震台网记录的地震观测资料进行对比.通过分析地面运动的峰值速度和持续时间的区域分布特征，发现：在青藏高原东北部边缘，较大的地形起伏对地面运动的峰值速度分布起主要影响作用；在青藏高原外围地区，地形起伏较小，而沉积层主要影响地面运动的峰值速度和持续时间，从而导致了明显的盆地效应，如地面运动的振幅放大和持续时间加长.因此，研究区剧烈的地形起伏和表层沉积层是影响地面运动的重要因素.
关键词: 岷县M_S6.6地震/
强地面运动/
地震波传播/
数值模拟/
峰值速度

Abstract:The 2013 M_S6.6 earthquake, which occurred in Minxian county, Dingxi city of Gansu province, caused huge casualties and economic losses. This earthquake, located at the junction of the northeastern margin of the Tibet Plateau and the southeastern Gansu, is the largest earthquake in this region for more than a century.According to seismic observation of this earthquake, the seismic ground motions differ greatly in different geological regions. In this study, we constructed a three-dimensional transmission medium model of the Minxian county and surrounding area based on the CRUST1.0 and SRTM30 models to investigate the observed spatial variation of seismic ground motions. The parallel three-dimensional finite difference method is adopted to simulate seismic wave propagation of the Minxian earthquake, and the synthetic seismograms are compared with the seismic observation data recorded by the digital seismic network in the study region.Analyses of the regional distribution of peak ground velocity (PGV) and durations of seismic ground motions show clear evidence of seismic site effects. In the northeastern Tibet Plateau, the relatively large topographic fluctuation influences the spatial distribution pattern of PGV. While in regions surrounding the Tibet Plateau where the topographic fluctuation is relatively small, the sedimentary layers mainly affect the spatial distribution of PGV and durations of seismic ground motions.Obvious basin effects such as the amplification and prolongation of the durations of seismic ground motions are observed. Therefore, both the drastic topographic fluctuation and the sedimentary layers in the study region are important factors that affect the seismic ground motions.
Key words:Minxian M_S6.6 earthquake/
Strong ground motion/
Seismic wave propagation/
Numerical modeling/
Peak ground velocity



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