Benefit Analysis Of The Two PSHA Maps Of China

Seismic zoning is one of the important countermeasures for prevention and mitigation of earthquake disasters in many countries in the world.It is the basis for taking various engineering measures and preparing national or regional social and economic development,land use planning,and so on.Zoning maps of China issued in 1990 and 2001 were prepared by means of the world wide adopted approach,Probabilistic Seismic Hazard Assessment,so the maps are called as PSHA maps.Test of the map has always been an international problem.In this dissertation,the economic loss and casualty estimations caused by earthquake damage of building with brick-concrete and steel-concrete respectively constructed from the 1990 and 2001 seismic zoning maps of our country are compared with the corresponding values of those if without fortification.Combined with the additional costs for the fortification,the earthquake prevention and disaster reduction benefits of the two PSHA maps are evaluated.The results show that during the two periods from 1990 to 2000 and from 2001 to 2015,the total additional cost in earthquake-resistant fortification of brick-concrete and steel-concrete structures in the country was 129.997 billion yuan and 665.461 billion yuan respectively.The damages of the two types of buildings caused total economic losses of 1.049716 trillion yuan,and 54506 deaths and 171158 seriously injuries during the earthquakes occurred in the periods.Compared with the corresponding losses and the casualties if without fortification,it is concluded that it has produced economic benefits of 1,819.4 billion yuan,a reduction of 283,260 deaths and 1,130,642 serious injuries.It has reached the level(1)benefit evaluated from the combination of two indicators,economic benefit and safety benefit.In order to study the decision of fortification level,the economic and safety benefits of seismic fortifications with intensities comprehensively plus or minus one degree on those from the two maps are evaluated respectively further in the dissertation.The results show that a comprehensive minus one degree fortification would reduce both economic and safety benefits.The decreasing rate could fall between 10.33% and 41.19%.If overall plus one degree fortification was adopted in the whole country(mainland area),the fortification cost would increase,and the corresponding economic benefits would decrease 0.60%～39.19%,and the safety benefit would increase 1.95%～55.20%.The test in this dissertation shows that the seismic zoning in our country have indeed exerted considerable benefits in earthquake prevention and disaster reduction.In the future,the risk level in preparing PSHA map could be appropriately increased from the test result.