1.The Second Monitoring and Application Center,China Earthquake Administration;2.Lanzhou Institute of Seismology,China Earthquake Administration;3.Beijing Earthquake Prevention Technology Development Co, Ltd.
The geological and geomorphological characteristics of the Dachaidan fault since late Quaternary are obtained, by means of interpretation of remote sensing data, field investigation, and differential GPS survey. The results show that the Dachaidan fault has been dominated by dextral thrust since late Quaternary. Measurement result is different in different geomorphic planes, showing obvious characteristics of multi-stage activity, which may be the recurrence of characteristic earthquakes in situ. Two paleoseismic events occurred before (3907.5 ± 72.5) a.B.P. and after (2402.5 ± 57.5) a.B.P., respectively. The recurrence period is about 1500 years, which indicates that the fault was strongly active in the Holocene, which is consistent with the frequent strong earthquake activities in the region in recent years.