岷县漳县6.6级地震前地震活动能量场分析  

Analysis of Energy Field of Seismic Activity before the Minxian-Zhangxian M_S6.6 Earthquake

作　　者：罗国富[1] 曾宪伟[1] 马禾青[1] 杨明芝[1] 

机构地区：[1]宁夏回族自治区地震局,宁夏银川750001

出　　处：《地震工程学报》2014年第2期314-319,共6页China Earthquake Engineering Journal

基　　金：地震科技星火计划项目(XH13024Y)

摘　　要：运用随机函数理论将地震释放能量作为地震活动场的基本要素,采用自然正交函数展开方法系统研究了2013年岷县漳县6.6级地震前震中区域地震活动能量场的时空特征。结果表明:地震前能量场的前4个主要特征值对应的典型能量场时间因子出现明显上升变化,可能是中短期时间异常特征;而主要典型场的空间等值线形成局部能量高值异常危险区,可能是中短期空间异常特征。最后分析不同时间段研究区域均值能量场空间变化图像,显示出岷县漳县6.6级地震前震中确实存在长期的能量场高值危险区背景,短期的能量场均值异常显著变化;宁夏南部及邻区也存在长期的能量场高值危险区背景,只是短期的能量场均值异常不明显,未来几年或稍长时间也存在发生强震的可能。The Minxian--Zhangxian Ms6.6 earthquake that occurred on Jul. 22,2013 is of great interest to the earthquake research community. In this paper,we describe the data we obtained for energy released by earthquakes and use the data to represent the basic elements of the seismic en- ergy field. Then, we discuss the spatiotemporal features of the regional seismic activity by the ran- dom function theory and the method of natural perpendicular function before 2013. The time weight factors of the typical energy field indicate that the energy field was increasing in this re- gion. The factors corresponded to the four key eigenvalues of the energy field before the Minxian --Zhangxian Ms6.6 earthquake. The spatial image of the key typical fields showed a danger zone having an abnormally high value relative to local energy, which may be the medium-short-time ab- normal. After analyzing the mean spatial image of the energy field in recent years, indications are that the Minxian--Zhangxian Ms6.6 earthquake occurred in a high release zone of energy field, which may be the medium-short-space abnormal. Finally, after analyzing the mean energy field of the image of different time periods and different study areas, we found that high values of the long-time energy field existed before the earthquake. Several conclusions can be drawn including that the zone of high values may be the danger zone, mean value of short-time energy field is sig- nificantly abnormal, and, furthermore,there is along-time high value danger region of seismic energy field in the south of the Ningxia area. Although the mean abnormal of short-time seismic en- ergy field is non-notable, our analysis suggests that there may be a strong earthquake in the region the next few years. Additionally, we analyzed the seismic energy field in the epicenter region of the Minxian--Zhangxian Ms6.6 earthquake. Our analysis indicates that there were different dis- tinct changes of four time factors of typical seismic energy fields from Sep. to Nov. 2011,Aug. to Nov. 2012,and Ap

关 键 词：岷县漳县6 6级地震 地震活动 能量场 随机函数 时间因子 高值异常 

分 类 号：P315.53[天文地球—地震学]