地震空间分布非空网格数的统计分布及地震活动增强-平静的定量检测
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摘要
以华北地区1980—2010年资料为例,以单位边长的网格覆盖研究区,考察中小地震空间分布非空网格数的变化.网格尺度足够小则非空网格数趋于该时段的地震数,网格尺度足够大则非空网格数为1.实际资料显示,当空间网格尺寸大于0.5°之后,对结果稳定性的影响逐渐减弱.中小地震空间分布非空网格数的变化与"背景"地震活动的空间扩展(增强)或收缩(平静)有关.不同网格尺寸条件下的非空网格数有基本一致的变化趋势,可能间接反映了区域应力的短时扰动或起伏.小地震有更高的丛集特性,随着震级下限的提高,不同网格尺寸非空网格数之间差异逐渐变小.华北地区小震活动非空网格数的频次分布符合统计正态分布,因而给定置信概率、依据正态分布密度函数可计算非空网格数的"正常"分布范围,超出此范围的数据可视为异常.统计显示,就华北地区而言,中小地震非空网格数"平静"型异常的预测效率最低,"增强"型异常具有最高的报警对应率,而同时考虑"增强"及"平静"的异常判据则具有最高的预报评分.这也意味着,华北中强地震前以"增强"型的中小地震活动异常为主.研究结果还显示,小地震时空活动格局的改变与后续中强地震似乎具有更强的统计关联特性.
Based on the earthquake data during 1980—2010 in North China region,we use the grids with l×l unit size to cover the area and investigate the variation of non-empty box number of earthquakes.When grid size l is small enough,the number of non-empty boxes tends to be equal to earthquake frequency.When grid size l is large enough,the number of non-empty boxes will be close to 1.This study shows that the influence of grid size on result stability is very weak when l is≥0.5°.The variation of non-empty boxes is related to the expanded(enhanced) or constricted(quiescence) patterns of earthquake spatial distribution.The numbers of non-empty boxes with different l roughly show a consistent changing tendency,potentially reflect the stress perturbation or undulation during a short time period indirectly.Small earthquakes are much more clustered,the difference between results with different threshold magnitude gradually tend to be small when threshold magnitude increases gradually.The non-empty grid numbers show a normal distribution,therefore the "normal" distribution range for non-empty grid numbers can be calculated with the given confident probability and the abnormal could be detected if the data is outside this "normal" range.The statistics show that in North China the forecasting efficiency is low for "quiescence" type abnormal,the "enhanced" type abnormal has a higher correct alarm rate,and the precursory criterion both by "enhanced" and "quiescence" type abnormal has a higher forecasting efficiency.This means that the precursory of small or moderate earthquakes before large earthquakes mainly displays as "enhanced" activity.The results also show that the pattern change of small or moderate earthquake spatial distribution seems to be related to coming large earthquakes more tightly.
Based on the earthquake data during 1980—2010 in North China region,we use the grids with l×l unit size to cover the area and investigate the variation of non-empty box number of earthquakes.When grid size l is small enough,the number of non-empty boxes tends to be equal to earthquake frequency.When grid size l is large enough,the number of non-empty boxes will be close to 1.This study shows that the influence of grid size on result stability is very weak when l is≥0.5°.The variation of non-empty boxes is related to the expanded(enhanced) or constricted(quiescence) patterns of earthquake spatial distribution.The numbers of non-empty boxes with different l roughly show a consistent changing tendency,potentially reflect the stress perturbation or undulation during a short time period indirectly.Small earthquakes are much more clustered,the difference between results with different threshold magnitude gradually tend to be small when threshold magnitude increases gradually.The non-empty grid numbers show a normal distribution,therefore the "normal" distribution range for non-empty grid numbers can be calculated with the given confident probability and the abnormal could be detected if the data is outside this "normal" range.The statistics show that in North China the forecasting efficiency is low for "quiescence" type abnormal,the "enhanced" type abnormal has a higher correct alarm rate,and the precursory criterion both by "enhanced" and "quiescence" type abnormal has a higher forecasting efficiency.This means that the precursory of small or moderate earthquakes before large earthquakes mainly displays as "enhanced" activity.The results also show that the pattern change of small or moderate earthquake spatial distribution seems to be related to coming large earthquakes more tightly.
引文
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韩渭宾,辛华,蒋国芳.2006.中国大陆及大华北、云南的地震平静指标:不同层次地震平静异常预测效能研究之二[J].四川地震,(3):1--9.
蒋长胜,吴忠良,史勇军.2004.中强震前地震活动矩释放加速现象(AMR)的普遍性问题[J].中国地震,20(2):119-125.
蒋海昆,董祥,苗青壮,吴琼,宋金.2009.不同温压条件下声发射应变能释放特征:加速模型参数物理含义的初步讨论[J].地球物理学报,52(8):2064--2073.
蒋海昆,侯海峰,周焕鹏,周翠英.2004.“区域-时间-长度算法”及其在华北中强地震中短期前兆特征研究中的运用[J].地震学报,26(4):151--161.
蒋海昆,杨马陵,孙学军,吕坚,阎春恒,吴琼,宋金,赵勇,黄国华,张华,姚宏,牟剑英,李金,曲均浩.2011.暴雨触发局部地震活动的一个典型例子:2010年6月广西凌云—凤山交界3级震群活动[J].地球物理学报,154(10):2606--2619.
蒋海昆,张流,周永胜,侯海峰,晁文海.2002.基于高温高压岩石破裂实验结果对部分地震学现象的解释[J].西北地震学报,24(2):113--122.
焦远碧,丁鉴海.2000.中等地震活动增强作为强震标志的研究[J].地震,20(2):16--19.
吕晓健,刘蒲雄.2000.华北地区强震前地震活动的异常增强[J].地震,20(3):43--47.
马胜利,蒋海昆,扈小燕,巴晶.2004.基于声发射实验结果讨论大震前地震活动平静现象的机制[J].地震地质,26(3):426--435.
平建军,张青荣,曹肃朝,边庆凯.2001.4级地震平静是华北地区强震前的一个重要震兆特征[J].地震学报,23(4):442--448.
宋俊高,王炜,陆锦花.1997.前兆性地震平静在中期预报中的定量研究[J].西北地震学报,19(3):37--43.
杨文政,马丽.1999.地震活动加速模型及其在中国的应用.地震学报,21(1):32--41.
张培震,邓启东,张国民,马瑾,甘卫军,闵伟,毛凤英,王琪.2003.中国大陆的强震活动与活动地块[J].中国科学:D辑,33(增刊):12--20.
Abercrombie R E,Agnew D C,Wyatt F K.1995.Testing a model of earthquake nucleation[J].Bull Seism Soc Amer,85(6):1873--1878.
Bowman D D,Quillon G.,Sammis C G,Sornette A,Sornette D.1998.An observational test of the critical earthquakeconcept[J].J Geophys Res,103(B10):24359--24372.
Bufe C G,Varnes D J.1993.Predictive modeling of the seismic cycle of the greater San Francisco Bay region[J].J Geophys Res,98(B6):9871--9883.
Habermann R E.1988.Precursory seismic quiescence:past,present and future[J].Pure Appl Geophys,126(2--4):279--318.
Hainzl S,Ogata Y.2005.Detecting fluid signals in seismicity data through statistical earthquake modeling[J].J Geophys Res,110,B05S07,doi:10.1029/2004JB003247:1--10.
Huang Q,Sobolev G A,Nagao T.2001.Characteristics of the seismic quiescence and activation patterns before the M=7.2Kobe earthquake,January17,1995[J].Tectonophysics,337(1--2):99--116.
JaumèS C,Sykes L R.1999.Evolving towards a critical point:A review of accelerating seismic moment/energy releaseprior to large and great earthquake[J].Pure Appl Geophys,155(2--4):279--306.
Kanamori H.1981.The nature of seismicity patterns before large earthquakes[M]∥Simpson D W,Richards P G eds.Earthquake Prediction--An International Review.Maurice Ewing Series(AGU4):1--19.
Keilis-Borok V.2002.Earthquake prediction:State-of-the-art and emerging possibilities[J].Annu Rev Earth PlanetSci,30:1--33.
Knopoff L,Levshina T,Keilis-Borok V I,Mattoni C.1996.Increased long-range intermediate-magnitude earthquake activity prior to strong earthquakes in California[J].J Geophys Res,101(B3):5779--5796.
Lei X,Yu G,Ma S,Wen X,Wang Q.2008.Earthquakes induced by water injection at～3km depth within theRongchang gas field,Chongqing,China[J].J Geophys Res,113,B10310,doi:10.1029/2008JB005604:1--12.
Ogata Y.1988.Statistical models for earthquake occurrences and residual analysis for point processes[J].J Amer StatAssoc,83(401):9--27.
Ogata Y.1989.Statistical model for standard scismicity and detection of anomalies by residual analysis[J].Tectonophysics,169(1--3):159--174.
Ohnaka M.1992.Earthquake source nucleation:aphysical model for short-term precursors[J].Tectonophysics,211(1--4):149--178.
Rundle J B,Klein W,Turcotte D L,Malamud B D.2000.Precursory seismic activation and critical-point phenomena[J].Pure Appl Geophys,157(11--12):2165--2182.
Shebalin P,Zaliapin I,Keilis-Borok V.2000.Premonitory raise of the earthquakes'correlation range:Lesser Antilles[J].Phys Earth Planet Inter,122(3--4):241--249.
Sobolve G A,Tyupkin Y S.1997.Low-seismicity precursors of large earthquakes in Kamchatka[J].Volcanol Seism,18:433--446.
Sobolve G A,Tyupkin Y S.1999.Precursory phases seismicity precursors,and earthquake prediction in Kamchatka[J].Volcanol Seism,20:615--627.
Wiemer S,Wyss M.1994.Seismic quiescence before the Landers(M=7.5)and Big Bear(M=6.5)1992earthquake[J].Bull Seism Soc Amer,84(3):900--916.
Wu Y M,Chiao L Y.2006.Seismic quiescence before the1999Chi-Chi,Taiwan,MW7.6earthquake[J].Bull Seism SocAmer,96(1):321--327.
Zller G,Hainzl S,Kurths J.2001.Observation of growing correlation length as an indicator for critical point behaviorprior to large earthquakes[J].J Geophys Res,106(B2):2167--2176.
韩渭宾,辛华,蒋国芳.2006.中国大陆及大华北、云南的地震平静指标:不同层次地震平静异常预测效能研究之二[J].四川地震,(3):1--9.
蒋长胜,吴忠良,史勇军.2004.中强震前地震活动矩释放加速现象(AMR)的普遍性问题[J].中国地震,20(2):119-125.
蒋海昆,董祥,苗青壮,吴琼,宋金.2009.不同温压条件下声发射应变能释放特征:加速模型参数物理含义的初步讨论[J].地球物理学报,52(8):2064--2073.
蒋海昆,侯海峰,周焕鹏,周翠英.2004.“区域-时间-长度算法”及其在华北中强地震中短期前兆特征研究中的运用[J].地震学报,26(4):151--161.
蒋海昆,杨马陵,孙学军,吕坚,阎春恒,吴琼,宋金,赵勇,黄国华,张华,姚宏,牟剑英,李金,曲均浩.2011.暴雨触发局部地震活动的一个典型例子:2010年6月广西凌云—凤山交界3级震群活动[J].地球物理学报,154(10):2606--2619.
蒋海昆,张流,周永胜,侯海峰,晁文海.2002.基于高温高压岩石破裂实验结果对部分地震学现象的解释[J].西北地震学报,24(2):113--122.
焦远碧,丁鉴海.2000.中等地震活动增强作为强震标志的研究[J].地震,20(2):16--19.
吕晓健,刘蒲雄.2000.华北地区强震前地震活动的异常增强[J].地震,20(3):43--47.
马胜利,蒋海昆,扈小燕,巴晶.2004.基于声发射实验结果讨论大震前地震活动平静现象的机制[J].地震地质,26(3):426--435.
平建军,张青荣,曹肃朝,边庆凯.2001.4级地震平静是华北地区强震前的一个重要震兆特征[J].地震学报,23(4):442--448.
宋俊高,王炜,陆锦花.1997.前兆性地震平静在中期预报中的定量研究[J].西北地震学报,19(3):37--43.
杨文政,马丽.1999.地震活动加速模型及其在中国的应用.地震学报,21(1):32--41.
张培震,邓启东,张国民,马瑾,甘卫军,闵伟,毛凤英,王琪.2003.中国大陆的强震活动与活动地块[J].中国科学:D辑,33(增刊):12--20.
Abercrombie R E,Agnew D C,Wyatt F K.1995.Testing a model of earthquake nucleation[J].Bull Seism Soc Amer,85(6):1873--1878.
Bowman D D,Quillon G.,Sammis C G,Sornette A,Sornette D.1998.An observational test of the critical earthquakeconcept[J].J Geophys Res,103(B10):24359--24372.
Bufe C G,Varnes D J.1993.Predictive modeling of the seismic cycle of the greater San Francisco Bay region[J].J Geophys Res,98(B6):9871--9883.
Habermann R E.1988.Precursory seismic quiescence:past,present and future[J].Pure Appl Geophys,126(2--4):279--318.
Hainzl S,Ogata Y.2005.Detecting fluid signals in seismicity data through statistical earthquake modeling[J].J Geophys Res,110,B05S07,doi:10.1029/2004JB003247:1--10.
Huang Q,Sobolev G A,Nagao T.2001.Characteristics of the seismic quiescence and activation patterns before the M=7.2Kobe earthquake,January17,1995[J].Tectonophysics,337(1--2):99--116.
JaumèS C,Sykes L R.1999.Evolving towards a critical point:A review of accelerating seismic moment/energy releaseprior to large and great earthquake[J].Pure Appl Geophys,155(2--4):279--306.
Kanamori H.1981.The nature of seismicity patterns before large earthquakes[M]∥Simpson D W,Richards P G eds.Earthquake Prediction--An International Review.Maurice Ewing Series(AGU4):1--19.
Keilis-Borok V.2002.Earthquake prediction:State-of-the-art and emerging possibilities[J].Annu Rev Earth PlanetSci,30:1--33.
Knopoff L,Levshina T,Keilis-Borok V I,Mattoni C.1996.Increased long-range intermediate-magnitude earthquake activity prior to strong earthquakes in California[J].J Geophys Res,101(B3):5779--5796.
Lei X,Yu G,Ma S,Wen X,Wang Q.2008.Earthquakes induced by water injection at～3km depth within theRongchang gas field,Chongqing,China[J].J Geophys Res,113,B10310,doi:10.1029/2008JB005604:1--12.
Ogata Y.1988.Statistical models for earthquake occurrences and residual analysis for point processes[J].J Amer StatAssoc,83(401):9--27.
Ogata Y.1989.Statistical model for standard scismicity and detection of anomalies by residual analysis[J].Tectonophysics,169(1--3):159--174.
Ohnaka M.1992.Earthquake source nucleation:aphysical model for short-term precursors[J].Tectonophysics,211(1--4):149--178.
Rundle J B,Klein W,Turcotte D L,Malamud B D.2000.Precursory seismic activation and critical-point phenomena[J].Pure Appl Geophys,157(11--12):2165--2182.
Shebalin P,Zaliapin I,Keilis-Borok V.2000.Premonitory raise of the earthquakes'correlation range:Lesser Antilles[J].Phys Earth Planet Inter,122(3--4):241--249.
Sobolve G A,Tyupkin Y S.1997.Low-seismicity precursors of large earthquakes in Kamchatka[J].Volcanol Seism,18:433--446.
Sobolve G A,Tyupkin Y S.1999.Precursory phases seismicity precursors,and earthquake prediction in Kamchatka[J].Volcanol Seism,20:615--627.
Wiemer S,Wyss M.1994.Seismic quiescence before the Landers(M=7.5)and Big Bear(M=6.5)1992earthquake[J].Bull Seism Soc Amer,84(3):900--916.
Wu Y M,Chiao L Y.2006.Seismic quiescence before the1999Chi-Chi,Taiwan,MW7.6earthquake[J].Bull Seism SocAmer,96(1):321--327.
Zller G,Hainzl S,Kurths J.2001.Observation of growing correlation length as an indicator for critical point behaviorprior to large earthquakes[J].J Geophys Res,106(B2):2167--2176.
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