Abstract:Based on the results of artificial seismic exploration, three profiles of boreholes are arranged in the North Shanlingzi Village of Dongli District, Zhongtang Village of Dagang District, and Beihuaidian Village of Ninghe County. Through the identification of microfossils and the test of strata age, the locations of the marine strata of boreholes are obtained in this work. The activity of the Cangdong fault is analyzed and studied through strata contrast and the paleomagnetic test results of BZ1 bore in Zhongtang Village. The result indicates that the activity sign of the Cangdong fault has not been found since the Late Pleistocene and its latest active age might be in the Middle Pleistocene. The contrast result of the marine strata of the Beihuandian borehole profile in the northern part of the Cangdong fault and the Zhongtang borehole profile in the southern part shows that there is a little difference in activity between the southern and northern sections of the Cangdong fault, divided by the Haihe fault. In addition, previous research has shown that the marine strata observation may better reflect the information of earthquakes. Besides the Cangdong fault, the marine strata of 21 boreholes on the south Tianjin fault, north Tianjin fault, and Haihe fault were also identified, and the location of marine strata will also be determined in the current Jiyunhe fault detection.
