中文摘要：

地震发生的物理机制和过程是还没有认识清楚的问题.此前人们将浅源地震归因于弹性回跳,根据这一观点和岩石实验结果计算得到的地震能量与实际观测结果有很大矛盾,被称之为＂热流佯谬＂.中源和深源地震发生在地幔区域,其成因也没有合理的解释.考虑到地壳和地幔是离散集合态物质体系及其慢动力学运动行为的基本特点,本文根据物理学原理,特别是近年凝聚态物理发展出来的相关新观念,并依据已有观测事实,从新的视角探究地震发生的物理机制.1）关于地壳岩石层中的应力分布：在不考虑构造力时,依据万物皆流的流变学原理,原始地壳岩石在自重压强长时间作用下,纵向和横向应力相同,没有差应力.大地构造力推动岩块滞滑移动挤压断层泥,施加于其他岩块,逐渐传递和积累.这种附加的横向构造力与原始岩石中应力叠加,形成地壳岩石层中的实时应力.由于断层泥属于颗粒物质体系,具有与岩石不同的力学特征,其弹性模量比岩石小得多,且随压强而增大,导致构造作用力随深度非线性增大.给出了地壳中构造应力分布及其变化规律.2）关于地壳岩石层强度：地壳岩石的自重会使岩石发生弹性—塑性转变.通过对弹性—塑性转变深度的计算,并根据实际情况分析,给出了地壳岩石弹性、部分塑性和完全塑性三个区域的典型深度范围.在部分塑性区,塑性体比例达到约10%以上时,发生塑性连通,这时岩石剪切强度由塑性特征决定.塑性滑移的等效摩擦系数比脆性破裂小一个数量级以上,致使塑性滑移时岩石剪切强度比脆性破裂小得多.同时,随深度增大,有多种因素使得岩石剪切屈服强度减小.另一方面,地震是大范围岩石破坏,破坏必然沿薄弱路径发生.因此,浅源地震岩石的实际破坏强度必定比通常观测到的岩石剪切强度值低.给出了地壳岩石平均强度和实际破

英文摘要：

The physical mechanism of earthquake remains a challenging issue to be clarified. Seismologists used to attribute shallow earthquake to the elastic rebound of crustal rocks. The seismic energy calculated following the elastic rebound theory and on the basis of experimental results of rocks, however, shows a large discrepancy with measurement—a fact that has been dubbed ＂the heat flow paradox＂. For the intermediate-focus and deep-focus earthquakes, both occurring in the region of the mantle, there is not any reasonable explanation yet. The current article will discuss the physical mechanism of earthquake from a new perspective, starting from the fact that both the crust and the mantle are discrete collective systems of matters with slow dynamics, as well as from the basic principles of physics, especially some new219101-22 concepts of condensed matter physics emerging in recent years. 1. Stress distribution in earth＇s crust： Without taking the tectonic force into account, according to the rheological principle that ＂everything flows＂, the vertical and the horizontal stresses must be in balance due to the effect of gravitational pressure over a long period of time, thus no differential stress in the original crustal rocks is to be expected. The tectonic force is successively transferred and accumulated via stick-slip motions of rocky blocks to squeeze the fault gouges, and then applied to other rocky blocks. The superposition of such additional horizontal tectonic force and the original stress gives rise to the real-time stress in crustal rocks. The mechanical characteristics of fault gouge are different from rocks as it consists of granular matters. Thus the elastic modulus of the fault gouge is much lower than that of rocks, and will become larger with increasing pressure. This character of the fault gouge leads to a tectonic force that increases with depth in a nonlinear fashion. The distribution and variation of tectonic stress in the crust are then specified. 2. Strength of crust rocks： The gra