相位加权叠加方法在探测鄂尔多斯东南缘地壳结构中的应用

摘要

本文利用在鄂尔多斯东南缘地区宽频带流动地震台阵记录的远震数据,提取各台站的接收函数,并利用相位加权方法进行单台多震叠加、H-κ叠加以及共转换点叠加,获得了研究区莫霍过渡带的深度及其变化趋势.研究结果显示,莫霍的深度由鄂尔多斯块体往东南方向逐渐变浅,在不同区域莫霍具有不同的特征:鄂尔多斯的莫霍深度在42～38 km；渭河—山西地堑的莫霍出现约3 km的上隆；熊耳—伏牛山的莫霍深度在35～33 km；河淮盆地的莫霍形态比较复杂.相位加权叠加方法能有效地压制相关性不好的噪音,在部分受噪音及沉积层多次波干扰的台站记录中,对突出莫霍的转换波Ps震相有很大的帮助.%In order to study the crustal structures in the southeastern margin of the Ordos Block, a portable broadband seismograph array with 22 stations was deployed in the study area. Instead of the linear stacking, a non-linear stacking technique named the phase-weighted stack (PWS) was used to stack the radial receiver functions for each station. The results show that the depth of Moho in the study area gradually decreases towards the southeast. The Moho discontinuity in different parts of the study area exhibits different features: the depth of Moho in the Ordos block is between 42 and 38 km; the Moho in Weihe-Shanxi graben bulges up by about 3 km; In the Xionger-Funiu Mountains, the depth of Moho is betweem 35 and 33 km; the Moho in the Hehuai basin appears to be complex. To conclude, the PWS Method is useful to enhance the S/N (signal/noise) ratio and determine the depth of Moho beneath the stations in the study area.