综合物探调查晋祠断裂对晋祠泉流域岩溶水控制作用效果分析

Control of the Jinci fault on karst water in the Jinci spring basin revealed by integrated geophysical surveys

研究晋祠断裂特征及其对晋祠泉流域岩溶水的控制作用,可为晋祠泉流域岩溶水运移规律的分析提供依据。本文利用可控源音频大地电磁法(CSAMT)、音频大地电磁法(AMT)、大地电磁法(MT)和大功率充电法等物探方法对晋祠断裂西南段断裂特征及其对晋祠泉流域岩溶水控水作用进行调查与研究。研究结果显示,晋祠断裂西南段走向北东—南西,倾向南东,倾角自浅至深由大变小,断裂带宽约250 m,影响深度大于1 km;晋祠断裂南东侧存在相对阻水地层,致使大部分岩溶水未进入太原盆地,推断该断裂为张性导水断层;在西山山地存在两个与晋祠断裂平行的岩溶水强径流带,其宽度在150~300 m之间。岩溶水通过晋祠断裂和强径流带对下游补给。

Research on characteristics of the Jinci fault and its controlling effect on karst groundwater in the Jinci spring watershed can facilitate analysis of the migration regularity of karst groundwater in the Jinci spring region.This work conducted such research by surveys using geophysical methods including Controlled Source Audio Frequency Magnetotelluric(CSAMT),Audio Frequency Magnetotelluric(AMT)and Magnetotelluric(MT).Results show that the southwest section of the Jinci fault strikes in NE-SW direction,dipping SE at angles becoming smaller from shallow to deep subsurface.Its width is about 250 m with influence depth over 1km.In the southeast side of the Jinci fault,rela⁃tively water-resistent strata makes most karst water failed to migrate into the Taiyuan basin,inferring the fault is a ten⁃sional water conducting fault.There are two karst water strong runoff zones parallel to the Jinci fault in Xishan moun⁃tains,the width of which is between 150 m and 300 m.Karst water supplies downstream area through the Jinci fault and strong runoff zones.