地球物理学进展 ›› 2019, Vol. 34 ›› Issue (4): 1635-1643.doi: 10.6038/pg2019CC0128

• 应用地球物理学Ⅱ(海洋、工程、环境、仪器等) • 上一篇    下一篇

微动测深法探测厚覆盖层结构——以北京城市副中心为例

李巧灵1,雷晓东1,*(),李晨1,冉伟彦2,杨全合1,何祎1   

  1. 1. 北京市地质勘察技术院,北京 100120
    2. 北京市地质矿产勘查开发局,北京 100195
  • 收稿日期:2018-09-23 修回日期:2019-05-21 出版日期:2019-08-20 发布日期:2019-08-30
  • 通讯作者: 雷晓东 E-mail:xiaodong@139.com
  • 作者简介:李巧灵,女,1983年生,博士,高级工程师,主要从事微动测量技术方面的研究.(E-mail: liqiaoling959@Foxmail.com)
  • 基金资助:
    通州城市副中心地区重大地质问题调查与评价项目(PXM2016_158203_000008);通州某建设新区深部地热资源勘查与示范项目(PXM2016_158307_000013);北京市平原区1:5万工程地质调查(12120114033901)

Exploring thick overburden structure by microtremor survey: a case study in the subsidiary administrative center

LI Qiao-ling1,LEI Xiao-dong1,*(),LI Chen1,RAN Wei-yan2,YANG Quan-he1,HE Yi1   

  1. 1. Beijing Institute of Geo-exploration Technology,Beijing 100120, China
    2. Beijing Institute of Geological Survey,Beijing 100195, China
  • Received:2018-09-23 Revised:2019-05-21 Online:2019-08-20 Published:2019-08-30
  • Contact: Xiao-dong LEI E-mail:xiaodong@139.com

摘要:

微动测深法通过提取表征介质物性差异的频散曲线,反演S波速度结构,为厚覆盖层结构划分提供地球物理依据.本文以北京城市副中心为例,在通州北部布设45个微动测深点,采用扩展空间自相关法(ESPAC)从预处理后的微动信号垂向分量中提取Rayleigh波相速度频散曲线,基于遗传搜索算法模型反演,获得各测点S波速度结构特征.沿北西向近似垂直地质构造走向切剖面AA’,利用剖面附近各测点反演结果,勾画主要地层结构.研究表明,微动测深可以有效探测新生界覆盖层厚度和结构,探明研究区新生界覆盖层厚度约为200~700 m,东南部甘棠凹陷沉积中心新生界覆盖层厚度约为700 m,凹陷发育受控于燕郊断裂和张家湾断裂.新生界覆盖层厚度和结构变化特征与区内搜集到的钻孔资料吻合.研究成果为北京副中心地区地质灾害防控和地热资源利用提供了科学依据.

关键词: 微动测深, 扩展空间自相关, 频散曲线, S波速度, 城市副中心, 通州

Abstract:

In order to study the thickness and structural characteristics of overburden layer in the northern area of Beijing subsidiary administrative center, microtremor survey were carried out and analyzed in this area. Based on 45 measurement data, phase velocity dispersion curve of Rayleigh wave was derived from vertical components of preprocessed microtremor signal by Extended Spatial Autocorrelation (ESPAC) method, S wave velocity was obtained at measurement locations through model inversion by genetic searching algorithm, and then 3D S wave velocity model was built using Kriging interpolation method, the thickness and 3D distribution of overburden were interpreted in the study area. Vertical geological structure along the AA’ section in direction NW, which is approximately perpendicular with the formation strike in the study area, are obtained using the inversion results of microtremor survey points near the section. The results are in good agreement with the measurement values acquired by other geological and geophysical techniques. Research shows that microtremor survey can effectively detect the thickness and formation of covering layer. In this study, the thickness of the overburden is about 200~700 m, while the thickness of the depositional center of Gantang depression in the southeast of the research area is about 700 m, and the depression is controlled by Yanjiao fault and Zhangjiawan fault. The results are consistent with drilling hole information collected in the study region. This research results provide scientific basis for the prevention of geological disasters and the utilization of geothermal resources for Tongzhou which is the subsidiary administrative center.

Key words: Microtremor survey, Extended Spatial Autocorrelation(ESPAC), Dispersion curve, S-wave velocity, Subsidiary administrative center, Tongzhou

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