鲁东地区视应力时空变化特征分析

地震 ›› 2014, Vol. 34 ›› Issue (4): 70-77.

鲁东地区视应力时空变化特征分析

王鹏, 郑建常

山东省地震局,山东济南250014

收稿日期:2014-03-20 修回日期:2014-05-19 发布日期:2020-09-11
作者简介:王鹏(1983-),男,山东东营人,工程师,主要从事地震活动性和数字地震学方面研究。
基金资助:
国家科技支撑计划(2012BAK19B04 -01-05)、地震局震情跟踪青年课题项目(2013020116)和山东省地震局合同制项目(14Y77)共同资助

Temporal and Spatial Variation of Apparent Stress in Eastern Shandong Province

WANG Peng, ZHENG Jian-chang

Earthquake Admini stra tion of Shandong P rovince, Jinan 250014, China

Received:2014-03-20 Revised:2014-05-19 Published:2020-09-11

摘要/Abstract

摘要： 利用山东数字地震台网记录到的山东东部地区2008年以来的地震波形资料,在去除地震序列的余震之后,采用Brune模型,并结合遗传算法反演计算了225 次Mr≥2. 0地震的视应力,讨论了视应力与震级的关系,分析研究了视应力的时空变化特征,并通过视应力的时空变化来研究该区应力状态的特征。结果表明:鲁东地区中小地震的视应力范围在0.06~3.91 MPa,平均应力水平在0.31 MPa,可作为该区的背景应力水平;视应力与震级呈正相关关系,随震级的增加而升高,利用稳态回归拟合初步得到适合于该区的定量统计关系;计算的视应力值减去由震级得到的理论视应力,去除震级的相关性干扰,得到差视应力,能更真实的反应该地区的应力变化特征;视应力的时间变化显示鲁东地区目前正处于应力的积累增强阶段,可能与近期鲁东地区震群频发有关;空间分布显示目前高视应力集中区主要分布在沂沭断裂带安丘段附近和烟台附近地区,对于山东地区年度危险区的判定有一定意义。

关键词: 震源参数, 视应力, 差视应力, 辐射能量, 鲁东地区

Abstract: Based on digital seismograms of eastern Shandong and the surrounding areas recorded by the Shandong digital seismic network since 2008,using Brune modelcom bined with genetic algorithm, we inversely calculate the apparent stress values of 225 earthquakes above magnitude 2. 0 in eastern Shandong. Furt hermore, we discuss the relationship between apparent stress and magnitude, analyze spatial and temporal variation of apparent stresses, and through the tem poral and spatial variation of apparent stress to study characteristics of local stress state. The results show that, firstly, the apparent stress range of small earthquakes in eastern Shandong is between 0. 06~3.91 MPa and mean stress level is 0. 31 MPa, which can be used as background stress level in the area; secondly, the apparent stress elevates with the magnitude increases which is positively correlated with the magnitude, we can get quantitative statistical relationships in the area using the robust fit; thirdly, we calculate difference apparent stress by subtracting the computed apparent stress through magnitude from the calculated apparent stress value, which can response to local stress variations more truly. In addition, time variations of apparent stress show that stress in eastern Shandong is currently in accumulation and enhance phase, whichis possibly related to the recent earthquake swarm in eastern Shandong. Spatial distribution show .that high apparent stress concentration area is mainly distributed in the area of Anqiu segment in Yishu fault and Yantai areas.

Key words: Seismic source parameter, Apparent stress, Difference apparent stress, Eastern Shandong province

中图分类号:

P315.7

王鹏, 郑建常. 鲁东地区视应力时空变化特征分析[J]. 地震, 2014, 34(4): 70-77.

WANG Peng, ZHENG Jian-chang. Temporal and Spatial Variation of Apparent Stress in Eastern Shandong Province[J]. EARTHQUAKE, 2014, 34(4): 70-77.

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