Abstract: Magnetotelluric (MT) sounding observations have been carried out along four profiles in the Xingtai earthquake area and its neighbouring regions. The results show characteristics of the geoelectrical structure of the crust and upper mantle for this region. The focal area looks like complex,while the surrounding area seems to be simple. The range of seismogenic depth is more complicated than the other depth range. Sharp changes of the electrical structure of the focal area indicate the hidden faults with steep angles. High conductive layers may represent the detachments of 10～20km depth. Upper mantle uplift is likely associated with upward migration of mantle material. These features are of great importance to understanding the tectonic background of the study region,the seismogenic structure,and relation between shallow and deep structure.

Key words: Magnetotelluric sounding, Resistivity, Crust-mantle structure, Xingtai earthquake

摘要： 用大地电磁测深(MT)方法在邢台地震区作了4条观测剖面,资料解释结果表明探测区地壳上地幔的电性结构主要特征为:震源区复杂,周边区简单;发震深度复杂,非发震深度简单;震源区电性突变,显示隐伏高角度断裂;高导层代表10km和20km深度的滑脱面;地幔上隆可能意味着地幔物质向上运移。这些观测结果对于了解测区构造背景、发震构造和深浅构造的关系有重要意义。

关键词: 大地电磁测深, 电阻率, 壳幔构造, 邢台地震