关键词: 浮山断裂、基岩断层面、滑动速率、1209年浮山地震

Abstract: Abstract: An earthquake of 6 occurred near Fushan country in the 9th year of DaDing period of the JIN Dynasty(in 1209), which caused a large number of casualties and property losses. Many experts and scholars speculated that the Fushan fault might be its seismogenic structure，But on in-depth research. The Fushan Fault is located on the east side of the Linfen Fault Basin in the Shanxi Fault Depression Zone. It is the boundary fault between the Linfen Fault Basin and the uplift area of the Taihangshan Fault Block. Predecessors have little research on the Fushan fault. This paper carries out a quantitative study on the activity and displacement rate of the Fushan fault in the Late Quaternary. First, remote sensing interpretation, fracture surface excavation, collection and testing of fault geomorphological samples in the area of Qianjiao Village of Fushan Fault were carried out, and the formation age of geomorphological bodies was obtained. It is determined that the latest stratum break event of the fault is later than 7 ka, which is a Holocene active fault and has the ability to generate earthquakes of magnitude 7 and above. A total of two phases of stratum break events have occurred on the Fushan Fault since 17 ka (Late Quaternary): the E1 event occurred between 17 ka and 7 ka, causing a displacement of 2.04m, the average diaplacement rate of the Fushan fault is 0.20mm/a. the E2 event occurred 7 ka to the present, causing a displacement of 3.93m. the average diaplacement rate of the Fushan fault is 0.56mm/a. The displacement rate of the fault has been increasing since the Late Pleistocene. The future seismic hazard of this fault is worthy of attention. This paper also uses land-based LiDAR scanning to obtain the topographic data of the fault plane on the Qiaojiapo Village bedrock section of the Fushan Fault (4.5km away from the Qianjiao Village section). The isotropic variogram method was used to calculate the fractal dimension of the fault surface morphology, and the morphological weathering zone was divided, and the two periods of the ancient seismic events since the Late Quaternary of the Fushan Fault were determined. From old to new, they are: E1 event caused a co-seismic displacement of 3.18m, and E2 event caused a co-seismic displacement of 2.51m. Studies have shown that the bedrock fault plane fractal method is an effective method for studying ancient seismic events in the bedrock area, and its ancient seismic period division is consistent with that of the sedimentary coverage area. Finally, this paper discusses the seismogenic structure of the 1209 Fushan earthquake with a magnitude of 6 , and believes that the seismogenic structure of the Fushan earthquake is the most likely to be the Fushan fault. However, due to the lack of a lower age limit and the only upper limit age that is far away from the historical earthquake time, it is necessary to conduct a more detailed investigation and research on the fault to determine whether there can be a revelation of ancient earthquake events with a renewed age and comparable magnitude.

Key words: Fushan fault、bedrock fault surface、diaplacement rate、Fushan earthquake in 1209