奉化-丽水-庆元断裂第四系活动性研究

A Study on the Activity at Quaternary of the Fenghua-Lishui-Qingyuan Fault

奉化-丽水-庆元断裂是浙江省内一条重要的北东走向断裂,自北向南穿越了浙江省大部地区,研究其活动性能为划分浙江地区潜在震源区以及重大工程的抗震设防提供科学依据。通过野外地质调查、物探等大量工作,结合对该断裂附近历史地震及现代小地震活动性分析,认为该断裂的宁波段、庆元段为晚更新世早期活动断层,具备5～6级地震的发震构造条件,其它地段地震构造相对稳定,发生5级及以上地震的可能性不大。

The Fenghua-Lishui-Qingyuan fault is an important fault in the NE direction in Zhejiang province. From north to south it crosses most areas of Zhejiang province. By researching on the activity of the fault, we can scientifically delimit the potential focal regions in Zhejiang and adopt the reasonable earthquake resistance protection for the important projects. Through field geologic investigation, shallow seismic prospecting and other method, combining with the activity of the historical earthquakes and the small earthquakes in modern times near the fault, we think that the Ningbo part and the Qingyuan part on the fault are active in early phase of late Quaternary and have the seismogenic tectonic condition to cause earthquake with M5-6. Because of the relatively stable seismotectonics condition, the possibility of causing earthquake with M over 5 on the other parts of the fault is not much.