物探化探计算技术2025，Vol.47Issue(2)：190-199,10.DOI:10.12474/wthtjs.20240301-0001
利用高频背景噪声研究蒲江-新津断裂带北段浅层速度结构
Velocity Structure of the northern section of the Pujiang-Xinjin Fault Zone from high-frequency background noise method
摘要
Abstract
The Pujiang-Xinjin Fault Zone(PXFZ)is the largest semi-concealed fault zone in the interior of the Chengdu Basin,whose southern segment is exposed at the surface,and the northern segment remains entirely concealed underground.Potential risks exist due to the fault near the main urban area,which may cause enormous casualties and property loss.However,the location and structure of the northern PXFZ remain ambiguous.In order to study the distribution and the underground velocity structure of the PXFZ,we extract Rayleigh surface wave dispersions from 0.1 s～2 s utilizing seismic ambient noise through 95 short-period seismometers in that area(deploy from April to May 2023).We obtain the three-dimensional shear wave velocity structure within 1.2 km of the near surface in this region.Combining the thickness distribution of sedimentary layers around Pengzhen Town,Shuangliu District,Chengdu City,and the seismic wave velocity data of the main strata in Chengdu City.We propose that the larger-scale low-velocity anomalies correspond to the concealed northern section of PXFZ.This fault zone passes through the northwest side of Pengzhen in Shuangliu,then continues northeastward,extending to the vicinity of Siyou Village in the southern part of Wenjiang District,and the smaller-scale low-velocity anomalies may indicate a north-east-oriented fractured zone.The detailed three-dimensional S-wave velocity structure of the northern PXFZ provides a fundamental reference for the subsurface exploration and geological hazard assessments of Chengdu City.关键词
蒲江-新津断裂带/背景噪声成像/相速度/剪切波速度结构Key words
Pujiang-Xinjin Fault Zone/background noise imaging/phase velocity/shear wave velocity structure分类
地质学引用本文复制引用
祝玉,孙新蕾,徐守浩..利用高频背景噪声研究蒲江-新津断裂带北段浅层速度结构[J].物探化探计算技术,2025,47(2):190-199,10.基金项目
自然科学基金(42074059),中国科学院基金项目(XDB42020304) （42074059）
