摘要
本文研究了流变介质内多断层的相互影响,通过对鲜水河断裂带的分析,对该断裂带提出一个不共线三断层的断裂力学模型.把介质考虑成流变的,用有限元法结合解析方法求解了流变断裂力学问题的应力、应变及能量场的时空变化.结果表明,多断层的力学场与单一断层的力学场相差甚远,在断层间形成了影响区.在影响区内应力集中,梯度大,分布复杂,应变能在影响区内形成较大范围集中.应变能等值线在孕震期间从影响区向外扩张,能量从外围流向断层区,流动在时空上都是不均匀的,孕育初期增加速率大,后期渐渐平缓.流向影响区的能量比其周围区域大,形成很大梯度.并讨论了地震前兆的某些特征.根据本文的结果,认为在道孚—乾宁—带发生地震的可能性较大.
In this paper we studied the interaction between several earthquake faults in theological medium. By analyzing Xianshuihe earthquake belts, we presented a fracture mechanical model with 3 faults, which are not co-linear. For ihis rheological fracture problem we solved the changes of stress, stain and elastic strain energy fields. The results show that. (1) The mechanical fields around these faults are very different from those of a single fault; effect zones are formed between faults, where stresses concentrate, strain energy gradient is very large and the mechanical fields distribute complicatedly. Also there are large areas of strain energy concentration in these effect zones. (2) During the seismogenetic process, the contours of strain energy extend outward from the effect zones, and energy flows inward to the faults. These flows are not uniform both in time and space. At the beginning, the increasing rate of energy is rasher large, and then gradually goes to zero. The flows of energy to the effect zones are higher than those to other places around faults, consequently large gradient zones were formed. Some characteristics of earthquake anomalies were discussed. According to the above mentioned results we infer that the next earthquake probably will occur in the zone between Qianning and Daofu.
出处
《地球物理学报》
SCIE
EI
CAS
CSCD
北大核心
1990年第3期308-318,共11页
Chinese Journal of Geophysics
基金
地震科学联合基金
关键词
流变断裂
断裂带
断层
相互作用
Rheological fracture, Multi-fault, Energy accumulation, Xianshuihe earthquake belt.
