摘要
2018年两次M_(s)5.0地震中,通海盆地强震动观测台阵获得了4个地表台站和1个井下台记录。基于钻孔资料和通海盆地新生界厚度模型,建立了通过两次地震震源和盆地的二维模型。基于二维谱元法,采用点源模型模拟了两次地震中强震观测台阵0.05~3 Hz速度记录,分析了台阵所处的盆地东北边缘体波和面波的传播过程。研究表明:对于观测台阵绝大部分记录,特别是速度峰值较大的记录,模拟和观测记录直达S波及盆地边缘发育的Rayleigh面波波形和幅值吻合较好。对于盆地深度100 m左右的3号和4号地表台,由于模型中盆地横向不均匀性的不精确及未考虑三维地盆结构的影响,S波和Rayleigh面波的吻合程度有所下降。从模拟和观测记录可见,入射体波在盆地东北部转化的Rayleigh面波较强,该面波包含频散显著、传播速度在150~350 m/s之间的基阶Rayleigh面波,以及频散不明显、传播速度在700~800 m/s之间的一阶Rayleigh面波。
In 2018,two M_(s)5.0 earthquakes were recorded by four surface stations and one downhole station in Tonghai basin strong motion observation array.Based on borehole data and Cenozoic thickness model of Tonghai basin,a two-dimensional model across the hypocenters and the basin is established.By using the two-dimensional spectral element method and point source model,velocity records were simulated with frequency band 0.05~3 Hz of the Tonghai basin strong motion observation array during the two earthquakes,and the propagation processes of seismic waves in the northeast of the basin edge are analyzed.The study shows that for most of the records especially with relative large PGV,both the waveforms and the amplitude of the direct S waves and basin edge generated Rayleigh waves of the simulated and the observed records fit well.For No.3 and No.4 surface stations where the basin depth is about 100 m,the fitness decreases,which may due to the imprecision of the basin transverse inhomogeneity and not considering the three-dimensional basin structure.It can be seen from the simulated and observed records that the Rayleigh waves transformed by incident body waves in the northeast of the basin are strong.The surface wave includes the fundamental-order Rayleigh waves with significant dispersion and propagation speed is between 150~350 m/s,and the first-order Rayleigh waves with insignificant dispersion and propagation speed is between 700~800 m/s.
作者
刘启方
王信博
崔建文
LIU Qifang;WANG Xinbo;CUI Jianwen(Key Laboratory of Structure Engineering of Jiangsu Province,Suzhou University of Science and Technology,Suzhou 215009,China;Yunnan Earthquake Agency,Kunming 650224,China)
出处
《自然灾害学报》
CSCD
北大核心
2023年第4期159-169,共11页
Journal of Natural Disasters
基金
国家自然科学基金项目(51978434)。
关键词
通海盆地强震动观测台阵
二维谱元法
Rayleigh面波
相关系数
Tonghai basin strong motion observation array
two-dimensional spectral element method
Rayleigh wave
correlation coefficient
