[关键词]
[摘要]
2013 年吉林松原前郭震群是一次典型的爆发式强震群活动,前郭震群MS≥5.0的5次主要地震事件呈现出了较为特殊的起伏特征。本文基于震源谱理论及震群型地震的特点,研究了该震群5 次主要地震事件的远场地震波辐射能的特征。选取国家级台站长春台,针对前郭震群的地震动观测记录,分析观测记录的时间域、频率域特征,结合考虑震群型地震的地震动谱与震源谱参数的关系,计算5 次地震事件的远场地震波辐射能,并进一步定量化地描述其在震源谱及地震波辐射能等方面的差异。研究结果表明,前郭震群中5 次主要地震事件的第2 次地震事件(No. 2)为整个震群的转折点,其震级上表现出来的衰减特征与其地震波能量释放特征呈现出了明显的非一致性。实际上,No. 2 事件是前郭震群中最重要的一次事件,主要表现为相对低的震级和相对高的远场地震波辐射能。
[Key word]
[Abstract]
The Qianguo MS5. 8 earthquake swarm of 2013 occurred in Qianguo,Jilin Province, China. There were 5 major earthquakes with MS≥5. 0 in the Qianguo earthquake swarm,the magnitude were MS5. 5,MS5. 0,MS5. 3,MS5. 8 and MS5. 0,respectively. In this study,we compared the characteristics of far-field seismic radiated energy of the major earthquakes based on the source spectrum and the ground motion spectrum of the earthquake swarm. We first research the ground motion spectrum of the 5 major earthquakes at the Changchun seismic station (CN2), a National station,with the recorded ground motions. Then we calculate the far-field seismic radiated energy referred to the relationships of the source spectrum in order to describe the variable characteristics of the Qianguo earthquake swarm. Research results indicate that the second earthquake (No. 2) of MS5. 0 on October 31 was the key event of the earthquake swarm, which followed the first MS5. 5 earthquake ( No. 1 ) on the same day. In fact,the magnitude decreased of the No. 2 comparing with the No. 1 is not agreed with the larger far-field seismic radiated energy. It needs to point out that,the No. 2 is the turning point event of the Qianguo earthquake swarm,which is the significant transition before the largest MS5. 8 earthquake occurrence.
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[基金项目]
国家自然科学基金(41404045)及中国地震局监测预报司震情跟踪合同制定向工作任务(2014020412 )联合资助