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重新审核了地震学文献中的两条基本原理,即远场弹性位移与动态断层面上的滑动速度成正比,以及地震断层上的平面动态滑动与双力偶体力等效等两条基本原理。我们指出,如果断裂发生于具有一定厚度的断层上,并且向前扩展的裂纹端部附近存在强度弱化区的话,则在与其等效的体力中会有一个附加的单力偶项,且在远场位移中也会有一个与向前扩展的强度弱化区内的应力降随时间增加的变化率成正比的附加项。我们还指出,与单力偶等效的体力并不违背牛顿力学原理,因为单力偶转矩为断层区内的旋转所平衡;于是,裂纹便辐射出扭转波与旋转形变场。
Two basic principles in the seismological literature were re-examined: the far-field elastic displacement is proportional to the sliding velocity on the dynamic fault plane, and the two basic principles of dynamic sliding of the plane on the fault and double-couple force are equivalent. We point out that if a fracture occurs on a fault of a certain thickness and there is a zone of strength weakening near the forwardly propagating crack tip, then there is an additional single-force term in its equivalent physical force, and in the far field There is also an additional term in displacement that is proportional to the rate of change of the stress drop over time in the area of weakening that is expanding forward. We also point out that the physical equivalent of a single force does not violate the Newtonian mechanics, because the single-couple moment is balanced by the rotation in the fault region; thus, the crack radiates torsional waves and rotational deformation fields.