Abstract

Info

Title:: Characteristics of Late Quaternary Tectonic Activity in the Middle Eastern Segment of the Southern Branch of Diebu Bailongjiang Fault, Gansu

Author(s):: LIU Xing-wang; YUAN Dao-yang; SHAO Yan-xiu; WU Zhao; 1. Lanzhou Institute of Seismology, China Earthquake Administration, Lanzhou 730000, Gansu, China;2. Lanzhou National Observatory of Geophysics, Lanzhou 730000, Gansu, China; 3. School of Earth Environmental Sciences, Lanzhou University, Lanzhou 730000, Gansu, China;4. Key Laboratory of Western China’s Environmental Systems of Ministry of Education, Lanzhou University, Lanzhou 730000, Gansu, China

Keywords:: active fault; Late Quaternary; slip rate; terrace; Holocene; Diebu-Bailongjiang fault; Gansu

Abstract:: Based on satellite image interpretation, field survey and geological mapping, the characteristics of Late Quaternary tectonic activity in the middle-eastern segment of the southern branch of Diebu-Bailongjiang fault, Gansu, were discussed. The results show that the activity of the middle segment of the southern branch of Diebu-Bailongjiang fault is stronger than that of the eastern segment; the characteristic along the middle segment is significantly linear, and the scar and fault scarp cutting through several terraces can be easily distinguished; the middle segment is active since Late Quaternary, and the elapsed time of the last event should be less than about 1 300 years; the middle segment is Holocene active fault; the activity of the eastern segment is obviously weakened, and there is no evidence of Holocene fault; the landform in the eastern segment is a linear valley, and the eastern segment is Late Pleistocene fault. According to the measurement of fault terrace and dating, the left-lateral and vertical slip rates are (1.3±0.1) mm and (0.39±0.04) mm per year in the middle segment of the southern branch of Diebu-Bailongjiang fault.