【摘要】 地震地表破裂是强地震活动中沿发震断层在地表形成的位移,它是包括震源因素、传播途径因素、场地地质条件因素等多种复杂因素的综合作用产物。地震地表破裂可以定量地加以描述。在假定基岩介质具有各项均匀刚性的前提下,对于一般的场地,地震地表破裂的危险性(概率P)大致可以确定为场地地震危险性(P1)、断层(P2)、场地第四系覆盖层(P3)的函数,即P=3Πi=1仪Pi。Pi值的确定可以通过多种途径来实现,本文在Pi值的确定过程中,以场地所在潜在震源区震级上限(Mu)为指标,P1=1.5874(Mu-6)-1;P2表示为断层发育状况、活动程度和断层最新活动性质的概率指数,P2=3Πi=1仪P2i;P3=nΠi=1仪kiwi,wi为分解的第i均质土层(i=1,2,…,n)对地震破裂的衰减系数,ki为破裂通过第i均质土层(i=1,2,…,n)与其下土层临界面的破裂传播折射损耗率。通过上面的计算可以得到一般场地条件下地震地表破裂的危险性估计,这一估计是相对保守的估计。更多还原

【Abstract】 As correlated with seismic focus,seismic wave spreading way,site geological conditions,etc.the seismic surface rupture can be described quantitatively by the factors above.To a site,the seismic surface rupture hazard(P) is determined a function of the seismic 3 risk(P1),fault(P2) and Quaternary layers(P3),that is P=3Πi=1Pi.In the determination of Pi,as for P1,the potential earthquake zone up-limited magnitude(Mu) is taken to be the target,P1=1.5874(Mu-6)-1;P2 is described as the function of faults determination(P21),activity(P22) and nearly activity features(P23),P2=3nΠi=1P2i;P3=Πi=1kiwi,wi is the weakening coefficient of the No.ievenlayers(i=1,2,…,n) to seismic surface rupture,ki is the seismic wave spreading refraction loss when the rupture come through the boundary of No.i & i+1(i=1,2,…,n) layers.After all,the estimate of probability index P is relatively conservative.更多还原