论文部分内容阅读
分析了由当地地震台网记录的 1 997年伊朗加恩 比尔兼德 (Ghean Birjiand)Zirkuh余震序列 .基于余震的分布 ,可以判断出一垂直的北西 南东走向的断层 ,其长度≥ 90km .加恩 比尔兼德Zirkun地震的断层破裂明显地表现为起始于震中区 ,单方向地向东南方向传播 .沿断层的余震分布剖面显示 ,余震分布的深度范围可达 2 0km .表明地震活动发生在上地壳 ,这一地区地震发生层的厚度≤ 2 0km .余震的分布表明 ,在主震的震源过程中块体西部是断层的上盘 .余震的时空分布表现出两个显著的空区 ,与地表断裂中所见到的间断一致 .可以得出这样的结论 :在主震和余震过程中第一个空区起着障碍体的作用 ,而第二个空区较深的部位在主震或余震的过程中发生了破裂 .地震后的前 1 0天 ,其余震的时间 频次衰减图象遵循修正的大森关系 ,而此后的余震序列非常好地遵循大森模型
The 1997 Iranian Ghean Birjiand Zirkuh aftershock sequence recorded by the local seismological network was analyzed and based on the aftershock distribution, a vertical north-southwest fault with a length of ≥ 90 km The fault rupture of the Enbit-Zirkun earthquake clearly manifests itself in the epicenter area and propagates to the southeast unidirectionally.The distribution of aftershocks along the fault shows that the depth of aftershocks can reach 20 km, indicating that the seismic activity occurred in the Upper crust, the thickness of the seismic layer in this area is less than 20 km. The distribution of aftershocks shows that the western part of the block is the upper plate of the fault during the source of the main shock. The spatial-temporal distribution of aftershocks shows two distinct empty areas The discontinuities seen in the surface rupture are consistent, and it can be concluded that the first vacant space acts as an obstacle in the main and aftershocks while the second, Aftershocks broke down during the first 10 days after the earthquake, the time-frequency attenuation images of the remaining aftershocks followed the modified Omori relationship, and aftershocks sequences followed very well following the Omori model