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地震活动区地面缓慢运动观测表明,地震前存在地倾斜和地形变异常。虽然这些异常的存在毫无疑问,但迄今仍没有理论解释。为此,根据地震孕育过程的唯象学概念提出了地面缓慢运动的理论模型。把介质(岩石层)模拟为被裂缝弱化带分隔的绝对刚性断块系,用标准线性体的流变模型描述这些地带中应力和形变的关系.断块运动从一块到另一块的传递是靠过渡带中物质形变来实现的.雪崩式不稳定裂缝形成模型是地震孕育过程模型的依据.地震孕育过程中的不同阶段断裂带中介质特征的变化与雪崩式不稳定裂缝形成模型是一致的,可用标准线性体模型参数的时间变化来描述。断块位移和过渡带应力的时间变化函数由线性微分方程组来确定数值解.垂直和水平的断块运动模拟结果证明,地震在断块间介质中孕育时发生地倾斜和断块相对位移异常.所得结果在性质上与地震前观测到的地倾斜和地形变异常特征相当一致。
The slow ground motion observations in the seismic activity area show that there are pre-seismic tilt and deformation anomaly. Although there is no doubt about the existence of these anomalies, so far there is no theoretical explanation. Therefore, based on the phenomenological concept of the earthquake breeding process, a theoretical model of slow movement of the ground is proposed. The medium (lithosphere) is modeled as an absolutely rigid fault block divided by weakening of the fracture and the rheological model of the standard linear body is used to describe the relationship between stress and deformation in these zones. The transfer of fault motion from one block to the other depends on Transitional zone material deformation to achieve.An avalanche instability crack formation model is the foundation of the earthquake breeding process model.Changes in the characteristics of the fracture medium in different stages of the earthquake gestation process are consistent with the avalanche instability crack formation model, It can be described by the time variation of the standard linear body model parameters. The function of time variation of block displacement and transitional stress is determined by the linear differential equations to determine the numerical solution. Vertical and horizontal block motion simulation results show that the earthquakes occurred in the interrupting medium when the geocentric inclinations and fault block relative displacement anomalies The results obtained are quite qualitatively consistent with the observed geostrophic anomalies and prehistoric earthquakes.