地震孕育体源流变模型(二)——应变场及其应用  

3-D RHEOLOGIC MODEL OF EARTHQUAKE PREPARATION (2). STRAIN FIELD AND ITS APPLICATIONS

作　　者：宋治平[1] 尹祥础[2] 梅世蓉[2] 

机构地区：[1]上海市地震局,中国上海200062 [2]中国地震局分析预报中心,中国北京100036

出　　处：《地震学报》2004年第2期121-131,共11页Acta Seismologica Sinica

基　　金：地震科学联合基金( 10 110 5 )资助

摘　　要：在弹性包体理论的基础上 ,建立了流变介质包体模型理论的应变场的理论解 ,导出流变介质中的包体在任意一点产生的正应变、剪应变及体应变的粘弹性解析解 ,即正应变、剪应变和体应变的表达式 .通过计算三维粘弹性介质中球形硬包体与软包体在地面引起的体应变场的时空演化过程 ,得到了一些非常有意义的结果 ,即球形硬包体在地面产生的体应变随时间的变化曲线出现了特征不同的 3个阶段 (α ,β ,γ) ,它与大量地形变资料出现的α ,β ,γ阶段相似 ,而球形软包体却没有这个特征 .这些结果对地震前兆的形态特征、前兆的象限性、前兆时空演化的阶段性、短临前兆突发性以及前兆异常时间的地区性等的解释具有启示意义 .这为地震前兆物理模式的建立提供了理论基础 ,并将为实现地震的物理预测发挥作用 .On the basis of the three dimensional elastic inclusion model, we derived the analytic expression of viscoelastic strain field, i.e., the analytic expression of viscoelastic strain at an arbitrary point ( x, y, z) in x axis, y axis and z axis produced by three dimension inclusion in the semi infinite rheologic medium defined by the standard linear rheologic model, namely the normal strains ε xx (r, t) , ε yy (r, t) and ε zz (r, t), the shear strains ε xy (r, t) and ε yx (r, t) , ε yz (r, t) and ε zy (r, t), ε xz (r, t) and ε zx (r, t), and the bulk strain θ (r, t). By computing the spatial temporal variation of bulk strain on the ground produced by a spherical rheologic inclusion in a semi infinite rheologic medium, we obtained some significant results that the bulk strain variation with time produced by a hard inclusion has three stages ( α, β, γ) with different characteristics, which are similar to those of most geodetic deformation curves, but not the case for those by a soft inclusion. It is meaningful that these theoretical results have been applied to explain preliminarily the characteristics of stage variation of spatial temporal evolution, the pattern and quadrant distribution of earthquake precursors, the changeability, spontaneity and complexity of short term and imminent term precursors. It offers a theoretical base to found the physical model of earthquake precursors and a reference to predict physically the earthquakes.

关 键 词：弹性包体理论 流变包体理论 应变场 粘弹性解析解 地震前兆 

分 类 号：P315.727[天文地球—地震学]