沈阳市F6断层的强地面运动分布模拟
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摘要
目的研究沈阳市F6断层在设定地震6.0级时的强地面运动分布,为避免城市活动断层的地震破坏和为重要建筑合理的抗震设防提供依据.方法通过断裂所处应力环境、形变特征及活动性、结构、规模、地震活动、深部构造等综合分析,确定F6断层的地震危险性.以深、浅层人工地震、钻探、多道直流电法、探地雷达和地脉动数据为基础,建立了沈阳市接近真实的三维地下速度结构模型,强地面运动计算采用了三维有限差分法和统计学格林函数法的合成方法.结果 F6断层为中更新世活动断裂,最大潜在地震震级为6.0级;F6断层的震源模型为具有两个Asperity(凹凸体)的矩形断层:一个最大18km2的Asperity和一个7km2的Asperity.在设定地震作用下,F6断层强地震动PGA的影响范围集中于F6断层两侧,最大值达到285gal;PGV、PGD的分布形态与PGA相似.结论 F6断层发生6.0级时在沈阳市能够形成带状的强地面运动分布,其幅值甚至超出大震设防水准.
In order to avoid earthquake damage related to active fault,and to provide anti-seismic basis for important buildings' fortification.This paper analyzes the strong grand motion distribution in Shenyang city based on the F6 fault of given Ms 6.0 earthquake,By analyzing F6's stress condition,deformation,activity,structure,scale,seismic activity,deep structure etc.the seismic hazard of F6 can be determined.Based on deep seismic reflection sounding,shallow seismic reflection sounding,trills,multichannel direct current sounding,geological radar data,the 3-D underground wave speed structure model is established and optimized.The synthetic means of 3-D limited differential and statistical Green' function are applied in the strong grand motion calculations.The F6 fault is mid-pleistocene active and its potential magnitude is 6.0.As to the F6 rectangular fault,it has 2 Asperities,one is about 18 km2 and the other is about 7 km2.Under Ms 6.0 earthquake on F6,the influencing area of PGA is around F6 fault,its maximum value can get to 285 gal,PGV、PGD are similar to PGA.When Ms 6.0 earthquake on F6 happens,it could appear a belted strong grand motion distribution in Shenyang city,its value even exceed the fortification level of large shock.
In order to avoid earthquake damage related to active fault,and to provide anti-seismic basis for important buildings' fortification.This paper analyzes the strong grand motion distribution in Shenyang city based on the F6 fault of given Ms 6.0 earthquake,By analyzing F6's stress condition,deformation,activity,structure,scale,seismic activity,deep structure etc.the seismic hazard of F6 can be determined.Based on deep seismic reflection sounding,shallow seismic reflection sounding,trills,multichannel direct current sounding,geological radar data,the 3-D underground wave speed structure model is established and optimized.The synthetic means of 3-D limited differential and statistical Green' function are applied in the strong grand motion calculations.The F6 fault is mid-pleistocene active and its potential magnitude is 6.0.As to the F6 rectangular fault,it has 2 Asperities,one is about 18 km2 and the other is about 7 km2.Under Ms 6.0 earthquake on F6,the influencing area of PGA is around F6 fault,its maximum value can get to 285 gal,PGV、PGD are similar to PGA.When Ms 6.0 earthquake on F6 happens,it could appear a belted strong grand motion distribution in Shenyang city,its value even exceed the fortification level of large shock.
引文
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[12]Kagawa T,Zhao B M.Modeling of the3-D basin structures for seismic wave simulations corresponded to information available in the target area[J].BSSA,2004,94(2):551-567.
[13]Sekiguchi,Irikura.Source inversion for estimating the continuous slip distribution on a fault introduction of Green's functions convolved with a correction function to give moving dislocation effects in sub-faults[J].Geo.J.Int.,2002,150(2):377-391.
[14]Somerville P G.Characterizing crustal earthquake slip models for the prediction of strong ground mo-tion[J].Seis.Res.Letters,1999,70(1):59-80.
[2]Boore D M.Stochastic simulation of high-frequency ground motion based on seismological models of thradiated spectra[J].BSSA,1983,73(5):1865-1894.
[3]Bouchon M.A simple method to calculate Green’s function for elastic latered media[J].BSSA,1981,71(2):959-971.
[4]Kamae K,Irikura K.A technique for simulating strong ground motion using hybrid Green’s function[J].BSSA,1998,88(1):357-367.
[5]刘保金.共偏移距地震反射波方法用于城市活断层探测[J].地震地质,2006,28(3):411-418.(Liu Baojin.Conbias seismic reflected wave means used in city active fault survey[J].Seismogeology,2006,28(3):411-418.)
[6]万波,廖旭.沈阳市(含抚顺)活断层探测与地震危险性评价[M].北京:地震出版社,2008.(Wan Bo,Liao Xu.Active fault surveying and seis-mic hazard evaluation for Shenyang city and Fushun city[M].Beijing:Earthquake Press,2008.)
[7]万波.沈阳市城区第四纪地层的划分[J].东北地震研究,2001,17(2):48-55.(Wan Bo.Quaternary layers division in Shenyang urban area[J].Seismological Research of Northeast China,2001,17(2):48-55.)
[8]万波.1765年沈阳51/2级地震发震构造判定[J].北京大学学报:自然科学版,2009,48(4):7-15.(Wan Bo.Seismogenic structure determination for the Shenyang51/2earthquake in1765[J].Acta Scientiarum Naturalium Universitatis Pekinensis,2009,48(4):7-15.)
[9]环文林.中国大陆内部走滑型发震构造的构造变形场特征[J].地震学报,1995,17(2):56-64.(Huan Wenlin.Structural deformation field for strike-slip seismogenic structure in China inland[J].Acta Seismologica Sinica,1995,17(2):56-64.)
[10]国家地震局.中国大陆2005年前强震危险性预测研究[C].北京:地震出版社,1997.(CSB.Strong earthquake forecasting in China main-land before2005[C].Beijing:Earthquake Press,1997.)
[11]中国地震局.JSGC-04中国地震活动断层探测技术系统技术规程[S].北京:地震出版社,2005.(CSB.JSGC-04Stipulation on technical system for China earthquake active fault surveying[S].Beijing:Earthquake Press,2005.)
[12]Kagawa T,Zhao B M.Modeling of the3-D basin structures for seismic wave simulations corresponded to information available in the target area[J].BSSA,2004,94(2):551-567.
[13]Sekiguchi,Irikura.Source inversion for estimating the continuous slip distribution on a fault introduction of Green's functions convolved with a correction function to give moving dislocation effects in sub-faults[J].Geo.J.Int.,2002,150(2):377-391.
[14]Somerville P G.Characterizing crustal earthquake slip models for the prediction of strong ground mo-tion[J].Seis.Res.Letters,1999,70(1):59-80.