赵国泽1, 刘国栋1, 王家映2. 1986: 北京-柏各庄剖面连续介质大地电磁反演解释. 地震学报, 8(2): 179-190.
引用本文: 赵国泽1, 刘国栋1, 王家映2. 1986: 北京-柏各庄剖面连续介质大地电磁反演解释. 地震学报, 8(2): 179-190.
ZHAO GUOZEup, LIU GUODONGup, WANG JIAYINGup2. 1986: INVERSION AND INTERPRETATION OF MAGNETOTELLURIC DATA ALONG THE BEIJING-BAIGEZHUANG PROFILE: A CONTINUOUS VARIATION MODEL IN RESISTIVITY. Acta Seismologica Sinica, 8(2): 179-190.
Citation: ZHAO GUOZEup, LIU GUODONGup, WANG JIAYINGup2. 1986: INVERSION AND INTERPRETATION OF MAGNETOTELLURIC DATA ALONG THE BEIJING-BAIGEZHUANG PROFILE: A CONTINUOUS VARIATION MODEL IN RESISTIVITY. Acta Seismologica Sinica, 8(2): 179-190.

北京-柏各庄剖面连续介质大地电磁反演解释

INVERSION AND INTERPRETATION OF MAGNETOTELLURIC DATA ALONG THE BEIJING-BAIGEZHUANG PROFILE: A CONTINUOUS VARIATION MODEL IN RESISTIVITY

  • 摘要: 在华北地区大地电磁测深工作的基础上,本文对北京——柏各庄剖面上的大地电磁观测资料,使用连续介质反演方法进行反演解释,获得了电性结构的最新结果。对构制的可接受地电模型的评价表明,本剖面内地壳中部普遍存在高导电带,上地幔内高导电带的深度变化较大,电阻率为1m的等值线深度,在沧县隆起为70多km,其西侧和东侧分别在60km和50km左右。上地幔高导电带的电阻率值由西而东有减小的趋势。这些结果与表层构造的对应关系说明,上地幔软流圈及地热场的横向不均一性,对地壳内部发生的构造运动有重要意义。

     

    Abstract: Amethod of continuous resiotivity variation is used for the inversion of the ma-gnetotelluric sounding data along the Beijing-Baigezhuang profile in the northern part of North China, and the latest result is obtained about the electrical structure of the crust and the upper mantle. To test the reliability of the acceptable models the Backus-Gilbert appraisal method is applied. In the electrical structure obtained the shallow low resistivity zones correspond to Cenozoic sediments. The high conductivity zones occur at the middle crust in the studied region, and they are thicker beneath depressions than those beneath uplifts. The depth of high conductivity zones in the upper mantle varies laterally and significantly. For example, the depth of resistivity contour of one ohm-meter is more than70km beneath the Cangxian uplift, about 60km beneath the central Hebei depression, and about 50 krn beneath the Huanghua depression. The resistivity value of the high conductivity zone in the upper mantle tends to decrease from west to east.The resistivity-depth curves within the crust are in good agreement with the velocity-depth curves for three principal tectonic units: the central Hebei depression, the Cangxian uplift and the Huanghua depression. The high conductivity zones in the upper mantle coincide with inverted velocity layers obtained by teleseismic data. The difference in electrical resistivity between uplift and depression reflects a lateral in-homogenety in the deep structure, and also has close relation Jo the temperature distribution in the depth. These results are interesting for further investigation of the tectonic movement and the evolution of the basins and the earthquake background of the North China plain.

     

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