【摘要】 地震的本质是一个能量长期积累和突发释放的地质过程。在板内地震特征分析的基础上,我们提出板内地震的三层次构造模式——软流圈上隆的深部构造、中地壳韧性流变层(低速高导层)及其上、下的强硬层组成的中部三明治构造和上地壳浅表脆性断裂构造。软流圈上隆使岩石圈减薄并为震源提供热能和机械能,提升地震三明治构造中韧性流变层的温度,且降低其粘度,相应地加大了高导层与高阻层的能干差,使得热能和机械能引起的应变能在两种不同流变性质介质边界附近强烈集中。三明治构造上面脆性断裂加速了应力集中,当活动断层达到三明治构造边界,即可触发地震的发生,引起应变能、热能的突然释放。基于以上模式,我们初步设计了对三层次构造信息的地震监测系统。更多还原

【Abstract】 Earthquake is a process concerning the long-term accumulation and abrupt release of energy in nature.On the basis of the analysis of the characteristics of intraplate earthquake, we present a three-level tectonic model for intraplate earthquake.It consists of a deep uplift structure of the asthenosphere, a middle sandwich structure,i.e.ductile-rheological layer sandwiched between competent layers, as the inner part in the middle crust and a shallow brittle faulting structure in the upper crust.The uplifting of the asthenosphere leads to thinning of the lithosphere of the local area around the upcoming epicenter.It supplies the thermal energy and mechanical energy to the epicenter area of the upcoming earthquake.It increases the temperature and lowers the viscosity of the inner ductile-rheological layer in the sandwich structure.The thermal energy increases the competent difference between the high-conductive layer and the high-resistive layers.The thermal and mechanical energy concentrates at the boundary area between the competent and incompetent layers.Active faulting above the sandwich structure accelerates the thinning of the lithosphere and highly concentrating the stress at the boundary between the competent and incompetent layers.When the active fault reaches the boundary of the sandwich structure, it triggers the intensive intraplate earthquake—inducing an abrupt release of the strain energy accumulated at the boundary area.On the basis of the model, we design a primary monitoring system for earthquake prediction from the information gaining from the three-level tectonic system.更多还原