%0 Journal Article %A TIAN Yi-ming %A YANG Zhuo-xin %A WANG Zhi-shuo %A SHI Jin-hu %A ZHANG Yang %A TAN Ya-li %A ZHANG Jian-zhi %A SONG Wei %A JI Tong-yu %T A PRELIMINARY STUDY OF THE SHALLOW EXPLORATION AND QUATERNARY ACTIVITIES OF THE FENGQIU SEGMENT OF THE XINXIANG-SHANGQIU FAULT %D 2023 %R 10.3969/j.issn.0253-4967.2023.01.008 %J SEISMOLOGY AND GEOLOGY %P 139-152 %V 45 %N 1 %X
Xinxiang-Shangqiu Fault starts from Yuhekou in the west and extends eastward into Anhui Province through Xinxiang, Yanjin, Fengqiu, Lankao, Minquan, Shangqiu and Xiayi, with a total length of about 400km and a general strike of NWW. It is a regional concealed fault in Henan Province and a boundary fault between northern North China depression and southern North China depression.
This study focuses on the Fengqiu section of Xinxiang-Shangqiu Fault, which is the boundary structure between the Kaifeng sag, Neihuang uplift and Dongpu sag. Controlled by the NE-NEE trending Changyuan Fault and Yellow River Fault at its east and west end, this fault section has a length of about 30km and controls the Mesozoic to early Cenozoic sedimentation in the Kaifeng sag and the south side of Dongpu sag.
In this paper, the shallow structural characteristics and Quaternary activities of Fengqiu section of the Xinxiang-Shangqiu Fault are revealed by the combination of reflection seismic exploration and drilling detection. Two shallow seismic exploration profiles and one composite drilling geological section are arranged across the fault.
The results of shallow seismic exploration show that the Fengqiu section of Xinxiang-Shangqiu Fault is NWW trending. It is a north-dipping normal fault accompanied by several nearly parallel normal faults, and the fault is still active since the Quaternary.
In the composite drilling geological section at Yaowu, the latest faulted stratum is a clay layer between borehole YW5 and YW7, and the buried depth of the upper breakpoint is between 57.00~61.50m. Combined with the dating results of the collected samples, it is comprehensively judged that the latest activity age of Fengqiu section is the middle of late Pleistocene. Since the middle of late Pleistocene, the whole region is in a relatively stable tectonic period. It is verified that the comprehensive detection method of shallow seismic exploration with drilling can effectively find out the accurate location of hidden faults.
The zone with strong vertical differential movement is often the zone where earthquakes occur. The vertical differential movement between Kaifeng sag and Neihuang uplift is very strong, and the difference reaches nearly