CAJ | 학술논문

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。
운용수궤함수이론장지진석방능량작위지진활동장적기본요소，채용자연정교함수전개방법계통연구료2013년민현장현6．6급지진전진중구역지진활동능량장적시공특정。결과표명：지진전능량장적전4개주요특정치대응적전형능량장시간인자출현명현상승변화，가능시중단기시간이상특정；이주요전형장적공간등치선형성국부능량고치이상위험구，가능시중단기공간이상특정。최후분석불동시간단연구구역균치능량장공간변화도상，현시출민현장현6．6급지진전진중학실존재장기적능량장고치위험구배경，단기적능량장균치이상현저변화；저하남부급린구야존재장기적능량장고치위험구배경，지시단기적능량장균치이상불명현，미래궤년혹초장시간야존재발생강진적가능。
The Minxian-Zhangxian MS 6.6 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 MS 6.6 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 MS 6.6 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 en-ergy 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 MS 6.6 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 Apr.to July 2013.In other words,a medium-short abnormal characteristic of the seismic energy field existed two years before the earthquake on July 22,2013.Secondly,by analy-zing the spatial contours of the two main seismic energy fields of the July 22,2013 earthquake our research indicates that a danger area of high value abnormal of seismic energy field existed near the Minxian and Zhangxian in the preceding five years.The danger area may have coincided with the spatial anomaly of the July 22,2013 earthquake.Thirdly,by analyzing distribution character-istics of spatial contours of the seismic energy field over different time periods,we concluded that there were spatial medium-short high value abnormal regions of earthquake energy at different times and for different epicenter areas before the July 22,2013 earthquake.Furthermore,strong earthquake danger may exist near several faults including the Lixian-Luojiapu fault and Diebu-Bailongjiang fault in the region of south-east of Gansu province,Xiangshan-Tianjingshan fault, Haiyuan fault,and Liupan mountain fault in the south of Ningxia.Fourthly,we can analyze time-space information for abnormal earthquake activity using the method of natural orthogonal func-tion.This type of analysis may help to forecast a strong earthquake or medium-strong earthquake, in a strong earthquake danger area.