摘要
利用地震学的三个经典经验模型(古登堡-里克特定律、修正的大森定律和巴特定律)和描述前震活动的Dieterich前震模型对2018年2月中国台湾花莲地震序列的特征进行了分析.将该地震序列分为M_L5.5前震序列、M_L5.5余震序列和M_L6.0余震序列等3段子序列进行研究,结果显示:利用古登堡-里克特定律得到的M_L5.5余震序列和M_L6.0余震序列的b值近似为1,M_L5.5前震序列的b值近似为0.5;利用修正的大森定律得到的M_L5.5余震序列和M_L6.0余震序列的p值近似为0.9;利用修正的巴特定律得出M_L5.5余震序列和M_L6.0余震序列的推定最大余震震级分别为M_L5.0和M_L5.5,与实际数据相比,其误差值约为0.1.通过拟合M_L5.5前震的发生率,分析可得M_L5.5前震序列的地震发生率N正比于1/(t_m-t),其中t(t<t_m)为前震发生时刻,t_m为M_L5.5地震发生时间,与Dieterich前震模型对前震现象的描述一致,表明其成因机制可能为主震成核过程中区域断层的次级断裂.
As we know,the statistical properties of an earthquake sequence are associated with three important empirical laws in seismology:Gutenberg-Richter law for the frequencymagnitude distribution,Bath law for the magnitude of the largest aftershock,and the modified Omori’s law for the temporal decay of aftershocks.In this paper these three laws are combined to study the February 2018 Hualien,Taiwan,China,earthquake sequence.In addition,a physics-based model proposed by Dieterich is used to describe the foreshock activities.The Hualien aftershock sequence is divided as three major sequences compounding with the M_L5.5 foreshock sequence,the M_L5.5 aftershock sequence and the M_L6.0 sequence.The results indicate that the b values associated with Gutenberg-Richter law for the M_L5.5 aftershock sequence and the M_L6.0 aftershock sequence are approximately 1,respectively.And b value of the M_L5.5 foreshock sequence are approximately 0.5.The p values with associated modified Omori’s law for the M_L5.5 and M_L6.0 aftershock sequences are both approximately 0.9,respectively.The estimated maximum aftershock magnitudes based on the modified form of Bath law are about M_L5.0 and M_L5.5,respectively,for M_L5.5 and M_L6.0 aftershock sequences,and the magnitude error is within△M=0.1 with a comparison to the recorded events.We also find that,for the M_L5.5 foreshock sequence,the seismicity rate N increases as a function of 1/(t_m-t),where t(t<t_m)is the time of the foreshock and tm is the time when the M_L5.5 earthquake occurred,respectively,which is consistent with the Dieterich earthquake triggering model,suggesting that the foreshock sequence may be related with mainshock nucleation process.
作者
尚园程
史保平
Shang Yuancheng;Shi Baoping(College of Earth and Planetary Science,University of Chinese Academy of Sciences,Beijing 100049,China)
出处
《地震学报》
CSCD
北大核心
2020年第1期1-11,120,共12页
Acta Seismologica Sinica
基金
国家自然科学基金(41574040)
国家国际科技合作专项(2015DFA21260)共同资助
作者简介
通信作者:尚园程,中国科学院大学固体地球物理学专业在读硕士研究生。2017年云南大学地球科学学院地球物理学专业毕业,获理学学士学位。主要从事地震触发机制和地震演化的数值模拟研究,e-mail:shangyuancheng17@mails.ucas.ac.cn
