一、前言在构造应力作用下,在地壳或上地幔某些部位逐渐积累起应变和应变能。当这种应变在某处达到岩石破裂的临界应变值或当应力达到岩石的破裂强度时,岩石就破裂而发生地震,释放了应变能。所积累起的应变能不是通过一个地震而是通过一系列地震释放完毕。这一系列地震在时间上是很靠近的,在地点上同处于一个震源体内,称为一个地震序列。 I. INTRODUCTION Under the action of tectonic stress, strain and strain energy are gradually accumulated in some parts of the crust or upper mantle. When this strain reaches the critical strain of rock at some point or when the stress reaches the rupture strength of the rock, the rock ruptures and an earthquake occurs, releasing the strain energy. The accumulated strain energy is not released by one earthquake but by a series of earthquakes. This series of earthquakes is close in time and co-located in a source body at a site called an earthquake sequence.