2022年门源M_(S)6.9和2016年门源M_(S)6.4地震序列比较分析  

Comparison of Aftershock Sequences between the 2022 Menyuan M_(S)6.9 Earthquake and the 2016 Menyuan M_(S)6.4 Earthquake in the Lenglongling Fault Zone

作　　者：孟令媛[1] 解孟雨 臧阳[1] Meng Lingyuan;Xie Mengyu;Zang Yang(China Earthquake Networks Center,Beijing 100045,China)

机构地区：[1]中国地震台网中心,北京100045

出　　处：《中国地震》2022年第1期1-11,共11页Earthquake Research in China

基　　金：中国地震局地震科技星火计划项目(XH22012YC、XH22011YA、XH20072)共同资助。

摘　　要：2022年1月8日青海省海北州门源县发生M_(S)6.9地震,震中距离2016年1月21日门源M_(S)6.4地震震中约33km,两次门源地震均发生在冷龙岭断裂附近,但在震源机制、主发震断层破裂过程及地震序列余震活动等方面显著不同。针对两次门源地震序列的比较分析,对研究冷龙岭断裂及其附近区域强震序列和余震衰减特征等具有重要研究意义。通过对比分析2022年门源M_(S)6.9地震和2016年门源M_(S)6.4地震余震的时空演化特征,发现二者在震源过程和断层破裂尺度上存在明显差异,前者发震断层破裂充分,震后能量释放充分,余震丰富且震级偏高;而后者发震断层未破裂至地表,余震震级水平偏低。综合分析两次门源地震序列表现出来的差异性,认为其可能与地震发震断层的破裂过程密切相关,且同时受到区域构造环境的影响。An M_(S)6.9 earthquake occurred near Menyuan County,Qinghai Province,China on January 8,2022.The epicenter of Menyuan M_(S)6.9 earthquake is about 33km only away from another M_(S)6.4 earthquake near Menyuan on January 21,2016.These two events both occurred near the Lenglongling fault zone,and the aftershocks of these two sequences were closely distributed.The focal mechanism of the 2022 Menyuan M_(S)6.9 earthquake is strike-slip with a moment magnitude of M W6.6,while the focal mechanism of the 2016 Menyuan M_(S)6.4 earthquake is thrust with a moment magnitude of M W5.9.It is of great significance to compare the characteristics of these two earthquake sequences to have a better understanding of the aftershock attenuation and other characteristics of sequences occurred near the Lenglongling fault zone and its adjacent areas.After comparing the temporal and spatial evolutional characteristics of the aftershocks of these two Menyuan earthquakes,it can be concluded that there are some differences between the source mechanism and rupture scale of these two events.As to the former one,the rupture of the seismogenic fault is much more sufficient.As a result,the energy released by this event is stronger and the seismicity of its aftershock is much more active.While to the latter one,the seismogenic fault failed to rupture to the surface,and the seismicity of its aftershocks is less intense.We also find that the differences between 2022 Menyuan M_(S)6.9 earthquake and 2016 Menyuan M_(S)6.4 earthquake sequences are considered to be closely related to the rupture process of the seismogenic fault and also affected by the regional tectonic environment.

关 键 词：门源M_(S)6.9地震 门源M_(S)6.4地震 冷龙岭断裂 余震活动 

分 类 号：P315[天文地球—地震学]