摘要
是否存在有助于预报的地震先兆?作者认为地震是以突发形式表现的构造变形,它发生前有一个由慢变快的物理过程,地震是应有先兆的.寻找先兆除受观测仪器、测点布局、以及地震先兆与主震之间关系复杂性等的限制外,能否抓住关键时段也十分重要.地震是一个力学过程,断层处于应力峰值强度后的亚失稳阶段时,已进入一个不可逆的变形阶段,标志着地震发生已不可避免.因此这个阶段与地震发生有唯一性的关系.
Whether earthquake precursors help for prediction do exist？ This paper attempts to answer this question from the mechanism of tectonic deformation. Because an earthquake is sudden slip on a fault, a physical process from slow to fast should happen prior to its occurrence. Consequently, observable precursors should appear before earthquakes. Whereas, to detect such precursors remains a difficult task. In addition to some limitations of the effort, such as observational instruments, deployment of measurement sites, and complicated relations between the precursor and main shock, it is an important step whether the crucial temporal stage can be recognized. An earthquake is a mechanical process. From the differential stress-time process, the deformation of the seismogenic fault should have four states, i.e. stability, meta-stability, meta-instability, and instability. In the stability and meta-stability stages, when the external force is removed, the strain of the fault can be recovered to some extent. As the causative fault enters the meta-instability stage, it is just the deformation stage dominated by release behind the stress peak strength. After this moment, even if no external force is loaded, the fault has entered an evolutional stage of self-instability, i.e. an irreversible deformation stage, indicating the seismic event is bound to occur. Thus, this stage has a relation of uniqueness with the burst of the earthquake.
出处
《科学通报》
EI
CAS
CSCD
北大核心
2016年第4期409-414,共6页
Chinese Science Bulletin
基金
国家自然科学基金(41172180
41572181)资助
关键词
地震先兆
亚失稳阶段
唯一性
earthquake precursor, meta-instability stage, uniqueness
