摘要
对中国大陆强震活动的时空分布特征进行分析,有助于中国大陆强震趋势的判定。由于地震目录完整性的限制,目前对中国大陆强震时间间隔的分析多基于1900年以来地震目录。因为记录时长相对较短,难以排除当前强震时序特征基于偶然的可能性,并且可能导致过拟合而影响预测效果。针对上述问题,本文根据2021—2030年中国大陆地震重点危险区确定工作中的相关资料,对合成地震目录进行了分析,结果表明区域地震活动强弱交替是一种普遍现象,当假设中国大陆活动断层具有准周期复发特征时,合成地震目录时序特征与当前目录最为接近。基于上述认识,使用适用范围更广的单参数指数分布拟合了中国大陆强震间隔,并结合相邻强震构造关联随时间的变化对2021年5月22日玛多7.4级地震后中国大陆的强震趋势进行了分析。结果表明,继玛多7.4级地震之后,未来两年中国大陆再次发生7级以上地震的概率较大,下次强震发生在2022年年底之前的概率为61.81%。下次强震发生在2021年的概率为30.58%,最有可能的发震区域是巴颜喀拉地块;下次强震发生在2022年的概率为44.97%,重点关注南北地震带中南段。
Analyzing characteristics of spatial and temporal distribution of strong earthquakes in Chinese mainland is benefit for determining trend of strong earthquakes in this region.Limited by completeness of catalogue,most analysis of strong earthquakes time intervals in Chinese mainland is on the basis of catalogue since 1900.Due to relative short duration of catalogue,it is difficult to exclude the possibility that current temporal characteristics of strong earthquakes are accidental,and it may cause over fitting which affects forecasting performance.To solve those problems,this paper analyzed synthetic catalogue based on the data from 2021—2030 key area for earthquake surveillance and protection in Chinese mainland.The results show that alternates clusters and quiescence is a common phenomenon for regional strong earthquakes.When supposed the active faults with quasi periodic recurrence behavior,temporal characteristics of synthetic catalogue are closest to the current catalogue.Based on understanding above,strong earthquake interval in Chinese mainland is fitted by the single parameter exponential distribution with wider application.Combined with structural correlation of adjacent strong earthquakes,trend of strong activity in Chinese mainland after the May 22,2021 Maduo M_(S)7.4 earthquake is analyzed.Results show that the next M_(S)≥7.0 magnitude in Chinese mainland is likely to happen in next two years,the probability being 61.81%before the end of 2022.The probability with the next strong earthquake will occur in 2021 is 30.58%,and the most likely area is Bayankala block;The probability of the next strong earthquake within 2022 is 44.97%,and the middle-south section of the North-South seismic belt should be noticed.
作者
王芃
邵志刚
石富强
尹晓菲
WANG Peng;SHAO Zhi-gang;SHI Fu-qiang;YIN Xiao-fei(Institute of Earthquake Forecasting,China Earthquake Administration,Beijing 100036,China;Shaanxi Earthquake Agency,Xi’an 710068,China)
出处
《地震》
CSCD
北大核心
2021年第4期1-14,共14页
Earthquake
基金
国家重点研发计划(2017YFC1500501)
中国地震局监测预报司震情跟踪定向工作任务(2021020506)。
关键词
中国大陆
强震时序特征
强震空间迁移
地震趋势
Chinese mainland
Temporal characteristics of strong earthquakes
Spatial migration of strong earthquakes
Seismic trend
