电阻率成像及浅层地震勘探在控盆构造探测中的应用——以万全断裂为例

The application of resistivity imaging and shallow seismic exploration to basin controlling structure——Taking Wanquan fault as an example

万全断裂是洋河盆地北缘断裂带组成断裂之一,控制沿线构造活动及地貌发育。断裂走向NE,倾向SE,在沟口处隐伏于第四纪覆盖层,采用电阻率成像和浅层地震联合勘探方法,获得该断裂隐伏段落综合物探异常,结合地质地貌调查,判定隐伏段落展布的具体位置、产状、活动特征及地下结构特征等。研究结果表明,万全断裂隐伏段落走向NE,倾向SE,倾角约75°,上断点埋深约20 m,20—240 m深度可见断裂破碎带(宽约10—20 m)物探异常特征及断裂两侧地层结构差异。该联合探测模式可有效探测复杂地质构造条件下的隐伏活动断裂,具有较强实用性,值得推广。

Wanquan fault is one of the faults in the fault zone of the northern margin of the Yanghe River basin. It controls the tectonic activity and the development of landforms along the northern margin of the basin. The strike of the fracture is in NE direction and the dip in SE. It is buried beneath the Quaternary overburden as it passed through Goukou. By means of resistivity imaging and shallow seismic exploration, we obtained comprehensive geophysical anomalies of faults. Combined with the geological survey, the specific location, occurrence, activity characteristics and underground structural features of the fault concealed passage are comprehensively determined. The results show that the strike and dip of concealed segment of Wanquan fault are also in NE and SE directions, respectively, while the dip angle is about 75°. The burring depth of fault is about 20 m. In the depth of 20—240 m, the fracture zone shows the anomalous features. And there is difference of formation structure existed between the sides of fracture. The comprehensive exploration pattern presented in this paper is one of the best methods for active fault investigation. It has strong promotional and practical value.