利用接收函数方法确定青藏高原东北缘近地表S波速度  

Constraining the sub-surface S-wave velocity of the northeastern margin of Tibetan Plateau with receiver functions

作　　者：钱银苹 沈旭章[1,3] 李翠芹 梅秀苹[1] 焦煜媛[1] QIAN YinPing;SHEN XuZhang;LI CuiQin;MEI XiuPing;JIAO YuYuan(Lanzhou Institute of Seismology,China Earthquake Administration,Lanzhou 730000,China;Earthquake Administration of Guangdong Province,Guangzhou 510070,China;School of Earth Science and Engineering,SunYat\|sen University,Guangzhou 510275,China;Earthquake Administration of Shandong Province,Jinan 250014,China)

机构地区：[1]中国地震局兰州地震研究所,兰州730000 [2]广东省地震局,广州510070 [3]中山大学地球科学与工程学院,广州510275 [4]山东省地震局,济南250014

出　　处：《地球物理学报》2018年第10期3951-3963,共13页Chinese Journal of Geophysics

基　　金：国家自然基金项目(41574077;41704057和41730212);国家重点研发计划(2017YFC1500100)资助

摘　　要：公式推导和数值实验都表明远震接收函数直达波幅度对近地表S波速度比较敏感,可以用于确定近地表(如沉积层)的S波速度值.本文利用该方法分析了青藏高原东北缘区域数字地震台网36个台站的远震资料,得到了研究区近地表S波速度分布特征.研究结果表明:在深度5±2.5km范围内,祁连山—河西走廊区域近地表S波速度均值较小;位于地形梯度带的甘东南区域近地表S波速度呈现较为复杂的分布.通过与该区域沉积层厚度结果对比,发现近地表S波速度与沉积层厚度呈现较好的负相关.本研究是对目前接收函数方法的有效补充,在探测研究近地表速度结构方面,相比人工地震方法其成本几乎可忽略且环保.在目前地震波观测数据海量增长的背景下,该方法对于确定不同区域近地表结构具有较大潜力.We systematically investigated the effect of sub-surface S-wave velocity on the direct wave(Pp)of receiver function by the formula derivation and numerical tests.The results indicated that the sub-surface S-wave velocity can be determined with the receiver function amplitude.This method has been applied to the teleseismic waveforms of 36 stations in the northeastern margin of Tibetan Plateau,and obtained the sub-surface S-wave velocity distribution within the depth range of 5±2.5 km.The results show that the sub-surface S-wave velocity is smaller in the Qilianshan-Hexi corridor region,and is more complicated in the southeastern Gansu region of terrain gradient zone.The comparison of the sedimentary thickness and the sub-surface S-wave velocity implies that the sub-surface S-wave velocity is negatively correlated with the sedimentary thickness.This method is an effective supplement to the application of receiver function.Comparing with the traditional active-source seismic exploration,the cost of our method is nearly ignorable,as well environmentally friendly.So this method also has great potential with the exponential increasing of seismological observations in the future.

关 键 词：接收函数 青藏高原东北缘 近地表S波速度 

分 类 号：P315[天文地球—地震学]