地震应变变化的理论量级与最大传递距离关系

RELATIONCHIP BETWEEN THEORETIC MAGNITUDE AND LONGEST PROPAGATION DISTANCE OF SEISMIC STRAIN CHANGE

为了与实际观测资料对比 ,用线弹性理论位错公式算出了各种断层的地震应变变化并进行了全面、系统的分析 ,归纳了一些特点 ,阐明了理论应变变化量级与其最大传递距离的关系。分析表明 :对于一定震级的地震 ,当断层出露地面、倾角为 4 5°、并且为倾滑运动时 ,一定量级的应变变化传递的距离最长 ;其中一个主应变传递得最远 ,其次为体应变 ,再其次为最大剪应变 ,另一个主应变的最大传递距离最短 ;泊松比和断层的长宽比的变化对应变传递距离的影响极小 。

An all-round theoretic analysis is carried out on maximum outreach of co-seismic strain changes of different magnitudes by using linear-elastic dislocation model.The longest propagation distances of certain co-seismic strain changes of different forms can extremely spread are given for the comparison with real measurements.According to the analysis,for an earthquake of certain magnitude,certain strain changes reach the farthest when the corresponsing seismic fault appears on the surface with a dip of 45° and dip-slips.One of the two principal strain changes of certain order spreads the greatest distance while dilatation is next to it,and then shearing,and finally the other principal strain.Influences of Poisson's ratio and the shape of fault are so small that can be neglected.