2017年九寨沟7.0级地震前不同级别地震空区的演化过程分析

Analysis of Seismicity Characteristics of the Jiuzhangou MS7.0 Earthquake on August 8,2017

摘要:

结合传统地震学方法与数字地震学方法，回顾总结了日常分析预报中针对九寨沟7.0级地震开展的相关工作，梳理总结了地震前提出的甘东南地震异常信息，进一步讨论了九寨沟地震前中期、短期及临震异常特征。通过分析九寨沟7.0级地震之前区域范围内不同震级活动图像，发现甘青川交界地区5级空区在震前向震中一侧收缩、4级地震超长平静458天、3级空区在震前4天被打破的现象，同时发现，震中附近区域震源机制一致性较高，反映了震源区的高应力水平。

Abstract:

This article integrates traditional seismological methods with digital seismological methods,reviews and summarizes the work of the Jiuzhaigou M_S7.0 earthquake in our daily analysis and forecast work. The anomalous information is summarized before the earthquake in southeast Gansu. Some mid-and short-term and impending earthquake anomalies related to the occurrence of this earthquake are also combed. The seismic activity images of different magnitudes in the area before the Jiuzhaigou M_S7.0 earthquake are analyzed. It is found that the M_S5.0 seismic quiescence in the western region of China is contracted to the epicenter before the earthquake. The super long calm time of the M_L4.0 seismic quiescence reaches 458 days and the M_L3.0 seismic gap is broken in 4 days before the earthquake. At the same time,the focal mechanism in the vicinity of the epicenter is highly consistent,which reflects the high stress level in the focal region. The research work does not only explore the potentially regular occurrence of this earthquake,but also provides a more valuable experience and methods of reference.