摘要
利用龙门山断裂带及其邻近地区地震台站的远震波形记录,采用时间域迭代反褶积技术求取接收函数,并用多次反射波能量扫描求极大值和波形叠加反演的方法(H-Kappa方法)计算出台站下方的莫霍面深度和波速比。结果显示:莫霍面位于扬子地台西缘部分向西侧倾斜缓降,深度在40～48 km变化,地壳平均波速比值为1.81;都江堰、汶川、耿达一带处在龙门山推覆体范围之内的莫霍面起伏变化不大,深度在45 km左右,地壳平均波速比值为1.707 5;龙门山断裂带西侧的松潘—甘孜地块的平均地壳波速比为1.76,莫霍面深度南面部分比北面深约10 km,呈南深北浅状。
Using tele-seismograms from stations in the region along and surrounding the Longmenshan fault zone, we stacked receiver-functions by means of time-domain iterative deconvolution, using a multiply energy scan and wave form modeling inversion method （ H-Kappa）, further estimated Moho depths beneath each station through the H- Kappa stacking method, and finally derived the distribution of both the Moho depth and the wave-to-velocity ratio （ Vp/Vs）. The results show ： The Moho of Western margin of the Yangtze Station ranges from 40 to 48 km, the wave- to-velocity ratio （Vp/Vs） is 1.81. The Moho boundary under Longmenshan nappe is of little ups and downs around 45 km, the wave-to-velocity ratio （Vp/Vs） is 1. 7075. The wave-to-velocity ratio （Vp/Vs） in Songpan-Ganzi block is 1.76. The crustal thickness of southern Songpan-Ganzi block is 10 km thicker than its northern counterpart.
出处
《防灾科技学院学报》
2012年第3期12-17,共6页
Journal of Institute of Disaster Prevention
