2016年青海门源M_S 6.4地震特征与地质构造

2016年青海门源M_S 6.4地震具有显著特征,如:余震强度低、能量释放水平低、震害较轻等。震区地震构造表现出一定规律性,如:冷龙岭断裂呈周期性破裂,发震断裂含多支相互斜交的分支断裂等。虽然地震前小震活动未能提供有价值的预测信息,但震中落入2015年甘肃省年度危险区。本文对此次地震的震源机制解、地震序列衰减、震害特点及冷龙岭断裂带构造进行分析,给出地震序列属性、发震断层及错动动力源,提出地震并未发生在冷龙岭主断裂的证据,从而为震区及邻区地震活动状态与孕震机制判定提供参考,并为后续震情判定提供震例与数据。

Principal features and seismic-tectonics of Qinghai Menyuan MS 6.4 earthquake in 2016

The seismic activity characteristic of Menyuan M_S 6.4 earthquake in 2016 is obvious, for example, the aftershock intensity is low, the energy release level is low, and earthquake damage is relatively lightand so on. The seismic structures show certain regularity, for example, Lenglongling fault zone shows periodic rupture, and contains multiple branch faults and so on. Although activity of small earthquakes before the earthquake failed to provide valuable predictive information, the epicenter of the earthquake falls into the annual danger zone of Gansu Province in 2015. The focal mechanism solution of the earthquake, attenuation of earthquake sequence, earthquake damage characteristics and structure of Lenglongling fault zone are analyzed in this article. Then, the attribute of seismic sequence, the closing date of the aftershock sequence, the power source for fault rupture are given. Some evidences that the earthquake did not occur in the main part of Lenglongling fault zone are presented. These purposes provide reference for state of seismic activity in earthquake zone and its adjacent area and determination of the mechanism of earthquake, and provide examples and data for determination of the subsequent earthquake.