岷县漳县6.6级地震前地震活动能量场分析
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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 energy field.Then,we discuss the spatiotemporal features of the regional seismic activity by the random 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 region.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 abnormal.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 significantly 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 energy 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 distinct 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 analyzing 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 22,2013earthquake.Thirdly,by analyzing distribution characteristics 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 22,2013earthquake.Furthermore,strong earthquake danger may exist near several faults including the Lixian-Luojiapu fault and DiebuBailongjiang 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 timespace information for abnormal earthquake activity using the method of natural orthogonal function.This type of analysis may help to forecast a strong earthquake or medium-strong earthquake,in a strong earthquake danger area.
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 energy field.Then,we discuss the spatiotemporal features of the regional seismic activity by the random 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 region.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 abnormal.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 significantly 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 energy 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 distinct 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 analyzing 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 22,2013earthquake.Thirdly,by analyzing distribution characteristics 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 22,2013earthquake.Furthermore,strong earthquake danger may exist near several faults including the Lixian-Luojiapu fault and DiebuBailongjiang 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 timespace information for abnormal earthquake activity using the method of natural orthogonal function.This type of analysis may help to forecast a strong earthquake or medium-strong earthquake,in a strong earthquake danger area.
引文
[1]严武建,朱朝霞,李晓峰,等.汶川8.0级地震前后陇南地区地震宏观异常调查及分析[J].西北地震学报,2011,33(1):67-71 .YAN WU-jian,ZHU Zhao-xia,Li Xiao-feng.et al.Investigation and Anijsis on Anomalies of Earthquake before and after Wenchuan MS8.0Earthquake in Longnan Area of Gansu Province[J].Northwestern Seismological Journal,2011,33(1):67-71 .(in Chinese)
[2]刘小风,梅秀萍,冯建刚,等.青藏高原北部地震基本活动状态定量评价[J].西北地震学报,2011,33(2):130-136.LIU Xiao-feng,MEI Xiu-ping,FENG Jian-gang,et al.Quantitative Estimating Basic State of Seismicity in Northern region of Qinghai-Xizang Plateau[J].Northwestern Seismological Journal,2011,33(2):130-136.(in Chinese)
[3]罗国富,屠泓为,马禾青,等.甘东南至陕甘宁中强震危险区地震活动能量场时空特征[J].西北地震学报,2012,34(2):132-137.LUO Guo-fu,TU Hong-wei,MA He-qing,et al.Space-time Distributed Characteristics on Energy field of Seismic Activity in Moderate Earthquake Hazard Area from the South East Part of Gansu Province to Shanxi-Gansu-Ningxia Region[J].Northwestern Seismological Journal,2012,34(2):132-137.(in Chinese)
[4]杨明芝,赵卫明.宁夏及邻近地区地震活动能量场的统计分析[J].地震学报,2004,26(5):516-522.YANG Ming-zhi,ZHAO Wei-ming.Statistical Analysis on Energy Field of Seismicity in Ningxia and Its Neighborhood Region[J].Acta Seismological Sinica,2004,26(5):516-522.(in Chinese)
[5]罗国富,杨明芝.云南地区地震活动能量场的时空分布特征[J].中国地震,2005,21(3):332-340.LUO Guo-fu,YANG Ming-zhi,Space-time Distributed Characteristics on Energy Field of Earthquake in the Yunnan Region[J].Earthquake Research in China,2005,21(3):332-340.(in Chinese)
[6]杨明芝,马禾青.汶川8.0级地震前龙门山断裂带能量场变化[J].中国地震,2011,27(3):260-267.YANG Ming-zhi,MA He-qing.Variation of Energy Field of Longmenshan Fault Zone before the Wenchuan MS8.0Earthquake[J].Earthquake Research in China,2011,27(3):260-267.(in Chinese)
[7]杨明芝,马禾青.汶川8.0级地震区域地震能量场分析[J].地球物理学报,2012,27(3):872-877.YANG Ming-zhi,MA He-qing.Analysis of Regional Seismic Energy Field berore Wenchuan MS8.0Earthquake[J].Progress in Geophys,2012,27(3):872-877.(in chinese)
[8]罗国富,杨明芝,马禾青,等.汶川8.0级地震前地震活动能量场中短期异常[J].地震,2011,31(3):135-142.LUO Guo-fu,YANG Ming-zhi,MA He-qing,et al.Intermediate and Short-term Anomalies of Seismic Activity Energy Field before the Wenchuan M8.0Earthquake[J].Earthquake,2011,31(3):135-142.(in Chinese)
[9]罗国富,屠泓为,马禾青,等.滇西北至滇西南强震危险区地震活动能量场分析[J].地震研究,2011,34(4):435-441.LUO Guo-fu,TU Hong-wei,MA He-qing,et al.Analysis on Energy Field of the Seismic Activity in Earthquake Hazard Area from the Northwest to the South of Yunnan[J].Journal of Seismological Research,2011,34(4)::435-441.(in Chinese)
[10]马禾青,杨明芝.2010年青海玉树7.1级地震能量场研究[J].地震研究,2012,35(4):485-490.MA He-qing,YANG Ming-zhi.Research on the Energy Field about Yushu M7.1Earthquake in Qinghai in 2010[J].Journal of Seismological Research,2012,35(4):485-490.(in Chinese)
①甘肃省地震局.甘肃省2012年度地震趋势研究报告.2011.
[2]刘小风,梅秀萍,冯建刚,等.青藏高原北部地震基本活动状态定量评价[J].西北地震学报,2011,33(2):130-136.LIU Xiao-feng,MEI Xiu-ping,FENG Jian-gang,et al.Quantitative Estimating Basic State of Seismicity in Northern region of Qinghai-Xizang Plateau[J].Northwestern Seismological Journal,2011,33(2):130-136.(in Chinese)
[3]罗国富,屠泓为,马禾青,等.甘东南至陕甘宁中强震危险区地震活动能量场时空特征[J].西北地震学报,2012,34(2):132-137.LUO Guo-fu,TU Hong-wei,MA He-qing,et al.Space-time Distributed Characteristics on Energy field of Seismic Activity in Moderate Earthquake Hazard Area from the South East Part of Gansu Province to Shanxi-Gansu-Ningxia Region[J].Northwestern Seismological Journal,2012,34(2):132-137.(in Chinese)
[4]杨明芝,赵卫明.宁夏及邻近地区地震活动能量场的统计分析[J].地震学报,2004,26(5):516-522.YANG Ming-zhi,ZHAO Wei-ming.Statistical Analysis on Energy Field of Seismicity in Ningxia and Its Neighborhood Region[J].Acta Seismological Sinica,2004,26(5):516-522.(in Chinese)
[5]罗国富,杨明芝.云南地区地震活动能量场的时空分布特征[J].中国地震,2005,21(3):332-340.LUO Guo-fu,YANG Ming-zhi,Space-time Distributed Characteristics on Energy Field of Earthquake in the Yunnan Region[J].Earthquake Research in China,2005,21(3):332-340.(in Chinese)
[6]杨明芝,马禾青.汶川8.0级地震前龙门山断裂带能量场变化[J].中国地震,2011,27(3):260-267.YANG Ming-zhi,MA He-qing.Variation of Energy Field of Longmenshan Fault Zone before the Wenchuan MS8.0Earthquake[J].Earthquake Research in China,2011,27(3):260-267.(in Chinese)
[7]杨明芝,马禾青.汶川8.0级地震区域地震能量场分析[J].地球物理学报,2012,27(3):872-877.YANG Ming-zhi,MA He-qing.Analysis of Regional Seismic Energy Field berore Wenchuan MS8.0Earthquake[J].Progress in Geophys,2012,27(3):872-877.(in chinese)
[8]罗国富,杨明芝,马禾青,等.汶川8.0级地震前地震活动能量场中短期异常[J].地震,2011,31(3):135-142.LUO Guo-fu,YANG Ming-zhi,MA He-qing,et al.Intermediate and Short-term Anomalies of Seismic Activity Energy Field before the Wenchuan M8.0Earthquake[J].Earthquake,2011,31(3):135-142.(in Chinese)
[9]罗国富,屠泓为,马禾青,等.滇西北至滇西南强震危险区地震活动能量场分析[J].地震研究,2011,34(4):435-441.LUO Guo-fu,TU Hong-wei,MA He-qing,et al.Analysis on Energy Field of the Seismic Activity in Earthquake Hazard Area from the Northwest to the South of Yunnan[J].Journal of Seismological Research,2011,34(4)::435-441.(in Chinese)
[10]马禾青,杨明芝.2010年青海玉树7.1级地震能量场研究[J].地震研究,2012,35(4):485-490.MA He-qing,YANG Ming-zhi.Research on the Energy Field about Yushu M7.1Earthquake in Qinghai in 2010[J].Journal of Seismological Research,2012,35(4):485-490.(in Chinese)
①甘肃省地震局.甘肃省2012年度地震趋势研究报告.2011.