Fault Activity Research And Seismic Risk Analysis Of Beijing District

Beijing, as the capital, will suffer from a great deal of injuries and loses in life and wealth if there is a earthquake over moderate magnitude. Therefore it is quite necessary to study the fault activity and make seismic risk analysis in Beijing City.On the basis of the results of seismic safety evaluation for engineering sites of Beijing, Hebei, Shanxi province and so on, the results of seismic microregionalization and the results of checking of Seismic ground motion parameter engineering item, gathering the latest data and working in the field for most time, we evaluate the seismic safety of the primary active faults in Beijing district, analyse the seismic risk of Beijing district with the professional soft recommended by China Seismological Bureau. The main achievement is listed.1. Due to the faults in the Beijing district play an important role, the geological structure of Beijing zone is very complicated. The active faults in the Beijing zone is mainly distributed in the north of Shanxi rifted zone and plain north china depressed zone. In this zone, the consistency with the active fault zone, bouguer gravity anomaly, aeromagnetic anomaly and the change of the thickness of crust have a Corresponding Relation in space. There are some clear subarea of the earthquake activity between strong and weak: earthquake is strong and high frequency in the north of Shanxi rifted zone and plain north china depressed zone, earthquake is weak in the uplift zone of mountanious region.2. There are 13 Quaternary period faults in Beijing district. The general trend of the activity of these faults is gradually from south to north, and it’s consistent with the activity of micro-earthquake. Comprehensive Analysis the condition of seismic and geological structure in Beijing district, it has a background of moderate earthquake occurrence and condition in Beijing district.3. Beijing district extends across the plain north china seismic belt and fen-wei seismic belt, the two seismic belts are the seismic strong activity zone. Sanhe-Pinggu M8 earthquake occurred in 1679 and Tangshan M7.8 earthquake occurred in 1978 had a very effect on Beijing district ,most of the earthquake occurred in Beijing district are strike-slip earthquake, and these earthquake are strong all. So, we forecast moderate earthquake will occur at this zone.4. The six district of Beijing city, daxing,tongzhou,shunyi,pinggu district is the area with seismic intensity ofⅧ, and the other zone of Beijing district is the area with seismic intensity ofⅦ.