Formation Analysis Of The Near North-West Surface Scarp In The North Of Zhengzhou City

Urban exploration activities in the existence of faults, and the study of their activities ,which provide an important scientific basis for the national economic and social development planning, major construction project siting and seismic fortification, had a great significance for the effective reduction of urban earthquake disaster. It also ensured the social stability and sustainable economic development.Research on active faults shows that topographical scarp is a major landscape mark which identifies active faults in topography, but not to all faults. There are still a large number of non-tectonic scarps. Therefore, the causes of landscape scarp became one of important factors on the identifying faults and exploring their activities.Laoyachen Fault is a NW - NWW fault, through the urban area of Zhengzhou, and therefore has an important influence on the urban development and construction. On the surface there was a scarp similar topographically paralleled to the Laoyachen Fault. However, related to the physical exploration data, there are also different results. And then, whether this scarp was shaped by the activity of Laoyachen fault has been controversial.This paper was supported by China Seismological Bureau of the projects "the Detection of Active Fault and Risk Assessment in Zhengzhou City " . Based on the use of shallow seismic exploration technology and joint drilling technology, and combined with information collected from previous research on the Laoyachen Fault ,the author studied the formation mechanism of the near North-West landscape scarp in the north of Zhengzhou City, which tried to provide a scientific basis for the activities of the Laoyachen Fault .Shallow seismic exploration aims to accurately identify the spatial distribution of the active faults near surface, detect its deep extension and the possibly concealed active fault, reveal the characteristic of the medium and the tectonic environment underground , which provide a basis for the seismic risk evaluation of the active faults.The joint drilling section is designed to test the reliability of the results from shallow seismic exploration, to identify the geological meaning of the shaft, rather than take the initiative to find fault. By comparing the lithology of the scarp up and down and the corresponding age-measurement of strata , the stratigraphic sequence could be detected successive or not.