乌鲁木齐地区活动断裂强震复发概率模型研究
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摘要
基于乌鲁木齐地区活动断裂的定量研究和区域地震活动性的分析,特别是对活动断裂(带)上的古地震和现代地震资料进行的系统、详细的分析与总结,以西山断裂为例,建立了反映该断裂地震地质特点和运动学属性的复发模式和概率模型。复发模式的建立兼顾了泊松和准周期2种模式。概率模型的建立包括2个层次上的内容:分析断裂上的古地震和历史强震目录(1863—2006年)以获得地表破裂型地震(MS≥6.7)的平均复发间隔;分析活动断裂所在潜在震源区的现代地震目录(1970—2006年,MS=2.0～5.0)以确定中等以上地震(MS≥5.0)的平均复发间隔;利用专家意见法组合相应的Poisson模型和BPT模型计算活动断裂各级地震的复发概率。计算结果表明,西山断裂地表破裂型地震的100a发震概率为4.0%,50a发震概率为3.6%。另外根据古地震资料、断裂规模和倾向滑动速率获得的西山断裂(带)的最大发震能力为7.5级。该研究综合应用了本地区的最新地震地质研究成果,在一定程度上较好地描述了断裂上地震活动的复杂性,可以较全面地评估乌鲁木齐地区活动断裂的地震危险性,该研究方法适合于地震地质资料较难完整获取的地区。
Based on the result of quantitative research on active faults,analysis of regional seismicity,and especially the detailed investigation and systematic summary on paleoearthquake in Urumqi region,the recurrence mode and probability models of Xishan Faults that reflect the seismic,geological and kinemics characteristics are established.The strong earthquake recurrence mode considers the Poisson mode and quasi-period mode and reflects the randomicity and determination with chanciness of seismicity on the fault.The probability model involves two levels of content:analyzing the paleoearthquake data and historical strong earthquake catalog on or near the faults to obtain the mean recurrence interval of surface-rupturing earthquakes(MS≥6.7),and analyzing the modern instrumental earthquake catalog(1970～present,and the size of these earthquakes is in the range of 2.0～5.0) of potential seismic source zone where the active faults locate.The calculation of seismic hazard probability of active faults utilizes the expert-opinion method to assign different weights to the models such as Poisson model and BPT model,and then incorporate the weighted probability result to construct combined model,which is the core of the method.This data-processing method has two advantages:taking complexity of strong earthquake recurrence mode into consideration and reducing the possibility of overestimating the seismic hazard of active faults.The result shows that the recurrence probability of surface rupturing earthquakes is 4.0% in the coming 100 years,and 3.6% in the coming 50 years.This result is consistent with that of the method based on stress environment analysis.The maximum magnitude of Xishan Faults(belt)is MS 7.5 estimated from paleoearthquake,dimension and dip-slip rate of fault,which is consistent with the upper limit magnitude of potential seismic source zone where the faults locate.This study integrates the newest research results on regional seismology and geology,better describes the complexity of seismic process along fault to a certain extent,and assesses comprehensively seismic hazards of active faults in Urumqi.This multidisciplinary method can be applied to the region like Urumqi where complete seismogeological data are unavailable.
Based on the result of quantitative research on active faults,analysis of regional seismicity,and especially the detailed investigation and systematic summary on paleoearthquake in Urumqi region,the recurrence mode and probability models of Xishan Faults that reflect the seismic,geological and kinemics characteristics are established.The strong earthquake recurrence mode considers the Poisson mode and quasi-period mode and reflects the randomicity and determination with chanciness of seismicity on the fault.The probability model involves two levels of content:analyzing the paleoearthquake data and historical strong earthquake catalog on or near the faults to obtain the mean recurrence interval of surface-rupturing earthquakes(MS≥6.7),and analyzing the modern instrumental earthquake catalog(1970～present,and the size of these earthquakes is in the range of 2.0～5.0) of potential seismic source zone where the active faults locate.The calculation of seismic hazard probability of active faults utilizes the expert-opinion method to assign different weights to the models such as Poisson model and BPT model,and then incorporate the weighted probability result to construct combined model,which is the core of the method.This data-processing method has two advantages:taking complexity of strong earthquake recurrence mode into consideration and reducing the possibility of overestimating the seismic hazard of active faults.The result shows that the recurrence probability of surface rupturing earthquakes is 4.0% in the coming 100 years,and 3.6% in the coming 50 years.This result is consistent with that of the method based on stress environment analysis.The maximum magnitude of Xishan Faults(belt)is MS 7.5 estimated from paleoearthquake,dimension and dip-slip rate of fault,which is consistent with the upper limit magnitude of potential seismic source zone where the faults locate.This study integrates the newest research results on regional seismology and geology,better describes the complexity of seismic process along fault to a certain extent,and assesses comprehensively seismic hazards of active faults in Urumqi.This multidisciplinary method can be applied to the region like Urumqi where complete seismogeological data are unavailable.
引文
[1]沈军,2006,乌鲁木齐经济技术开发区二期及延伸用地地震小区划研究报告。
陈立春,冉勇康.2002.京西北盆岭构造区强震复发概率模型及地震潜势的定量评估[J].地震地质,24(1):92—99.CHEN Li-chun,RAN Yong-kang.2002.Probability model for strong earthquake recurrence and quantitative estimatesof seismic potential in the basin and range province,northwest of Beijing[J].Seismology and Geology,24(1):92—99(in Chinese).
邓起东.2002.城市活动断裂探测和地震危险性评价问题[J].地震地质,24(4):601—605.DENG Qi-dong.2002.Exploration and seismic hazard assessment of active faults in urban areas[J].Seismology andGeology,24(4):601—605(in Chinese).
邓起东,陈立春,冉勇康.2004.活动构造定量研究与应用[J].地学前缘,11(4):383—392.DENG Qi-dong,CHEN Li-chun,RAN Yong-kang.2004.Quantitative studies and applications of active tectonics[J].Earth Science Frontiers,11(4):383—392(in Chinese).
冯先岳.1997.新疆古地震[M].乌鲁木齐:新疆科技卫生出版社.1—250.FENG Xian-yue.1997.Paleoearthquake in Xinjiang[M].Xinjiang Science,Technoloy and Sanitation Press,Urumqi.1—250(in Chinese).
胡军,栾超群,胡方秋,等.1996.乌鲁木齐西山断层新构造运动特征[J].新疆地质,14(3):228—237.HU Jun,LUAN Chao-qun,HU Fang qiu,et al.1996.Neotectonic characteristics of Xishan Faults,Urumqi[J].Xinjiang Geology,14(3):228—237(in Chinese).
蒋溥,戴丽思.1993.工程地震学概论[M].北京:地震出版社.JIANG Pu,DAI Li-si.1993.An Introduction to Engineering Seismology[M].Seismological Press,Beijing(in Chinese).
冉洪流,周本刚.2004.布朗模型在北京西北地区的应用[J].地震学报,26(增刊):96—102.RAN Hong-liu,ZHOU Ben-gang.2004.Application of Brownian model to the northwestern Beijing,China[J].ActaSeismologica Sinica,26(suppl):96—102(in Chinese).
冉洪流.2004.海原断裂带M≥6.7地震概率及其震级分布[J].地震学报,26(6):609—615.RAN Hong-liu.2004.Earthquake probabilities and magnitude distribution(M≥6·7)along the Haiyuan fault,northwestern China[J].Acta Seismologica Sinica,26(6):609—615(in Chinese).
冉勇康,邓起东.1999.大地震重复特征与平均重复间隔的取值问题[J].地震地质,21(4):316—323.RAN Yong-kang,DENG Qi-dong.1999.Recurrence behavior of large earthquakes and how to take average recurrenceinterval of large earthquakes[J].Seismology and Geology,21(4):316—323(in Chinese).
闻学泽.1995.活动断裂地震潜势的定量评估[M].北京:地震出版社.1—150.WEN Xue-ze.1995.Quantitative Estimates of Seismic Potential on Active Faults[M].Seismological Press,Beijing.1—150(in Chinese).
闻学泽.1998.时间相依的活动断裂分段地震危险性评估及其问题[J].科学通报,43(14):1457—1466.WEN Xue-ze.1998.Assessment of time-dependent seismic hazards on segments of active fault,and its problems[J].Chinese Science Bulletin,43(14):1457—1466.
张红艳.2006.新疆地区现代构造应力场非均匀性及成因机理分析[D]:[学位论文].北京:中国地震局地壳应力研究所.ZHANG Hong-yan.2006.Research on heterogeneity and dynamic genesis of the present tectonic stress field in Xinjiangarea[D].Master degree thesis.Institute of Crustal Dynamics,CEA,Beijing(in Chinese).
朱金芳.徐锡伟,黄宗林,等.2005.福州市活断层探测与地震危险性评价[M].北京:科学出版社.ZHU Jin-fang,XU Xi-wei,HUANG Zong-lin,et al.2005.Active Faults Exploration and Seismic Hazard Assessment inFuzhou City[M].Science Press,Beijing(in Chinese).
Bai Meixiang.1998.Paleoearthquake activity in Tadzhikistan and Xinjiang,China[J].Inland Earthquake,12(2):161—166.
Cornnel C A.1968.Engineering seismic risk analysis[J].Bull Seism SOC Am,58:1583—1606.
Ellsworth W L.1999.A physically based earthquake recurrence model for estimation of long-term earthquakeprobabilities[R].US Geol Surv Open-File Rept.99—552.
Matthews M V,Ellsworth W L,Reasenberg P A.2002.A Brownian model for recurrent earthquakes[J].Bull SeismSoc Amer,92:2233—2250.
Reid HF.1910.The mechanics of the earthquake,in the California earthquake of April18,1906[A].In:Report ofthe State Earthquake Investigation Commission.Carnegie Institution of Washington Publication87,2.192.
Wells D L and Coppersmith K J.1994.New empirical relationships among magnitude,rupture length,rupture width,rupture area,and surface displacement[J].Seismological Society of America Bulletin,84(4):974—1002.
Working Group on California Earthquake Probabilities.1988.Probabilities of large earthquakes occurring in Californiaon the San Andreas fault[R].US Geol Surv Open-File Rep.88—398.
Working Group on California Earthquake Probabilities.1990.Probabilities of large earthquakes in the San FranciscoBay Region,California[J].US Geol Surv Circ,1053—1103.
Working Group on California Earthquake Probabilities.1995.Seismic hazards in Southern California:probableearthquakes,1994—2024[J].Bull Seis Soc Am,85:379—439.
Working Group on California Earthquake Probabilities.1999.Earthquake probabilities in the San Francisco Bay Region2000—2030:A Summary of findings[R].US Geological Survey Open-File Report.99—517.
Working Group on California Earthquake Probabilities.2003.Earthquake probabilities in the San Francisco Bay Region2002—2031[R].US Geol Surv Open-File Rept.3—214.
陈立春,冉勇康.2002.京西北盆岭构造区强震复发概率模型及地震潜势的定量评估[J].地震地质,24(1):92—99.CHEN Li-chun,RAN Yong-kang.2002.Probability model for strong earthquake recurrence and quantitative estimatesof seismic potential in the basin and range province,northwest of Beijing[J].Seismology and Geology,24(1):92—99(in Chinese).
邓起东.2002.城市活动断裂探测和地震危险性评价问题[J].地震地质,24(4):601—605.DENG Qi-dong.2002.Exploration and seismic hazard assessment of active faults in urban areas[J].Seismology andGeology,24(4):601—605(in Chinese).
邓起东,陈立春,冉勇康.2004.活动构造定量研究与应用[J].地学前缘,11(4):383—392.DENG Qi-dong,CHEN Li-chun,RAN Yong-kang.2004.Quantitative studies and applications of active tectonics[J].Earth Science Frontiers,11(4):383—392(in Chinese).
冯先岳.1997.新疆古地震[M].乌鲁木齐:新疆科技卫生出版社.1—250.FENG Xian-yue.1997.Paleoearthquake in Xinjiang[M].Xinjiang Science,Technoloy and Sanitation Press,Urumqi.1—250(in Chinese).
胡军,栾超群,胡方秋,等.1996.乌鲁木齐西山断层新构造运动特征[J].新疆地质,14(3):228—237.HU Jun,LUAN Chao-qun,HU Fang qiu,et al.1996.Neotectonic characteristics of Xishan Faults,Urumqi[J].Xinjiang Geology,14(3):228—237(in Chinese).
蒋溥,戴丽思.1993.工程地震学概论[M].北京:地震出版社.JIANG Pu,DAI Li-si.1993.An Introduction to Engineering Seismology[M].Seismological Press,Beijing(in Chinese).
冉洪流,周本刚.2004.布朗模型在北京西北地区的应用[J].地震学报,26(增刊):96—102.RAN Hong-liu,ZHOU Ben-gang.2004.Application of Brownian model to the northwestern Beijing,China[J].ActaSeismologica Sinica,26(suppl):96—102(in Chinese).
冉洪流.2004.海原断裂带M≥6.7地震概率及其震级分布[J].地震学报,26(6):609—615.RAN Hong-liu.2004.Earthquake probabilities and magnitude distribution(M≥6·7)along the Haiyuan fault,northwestern China[J].Acta Seismologica Sinica,26(6):609—615(in Chinese).
冉勇康,邓起东.1999.大地震重复特征与平均重复间隔的取值问题[J].地震地质,21(4):316—323.RAN Yong-kang,DENG Qi-dong.1999.Recurrence behavior of large earthquakes and how to take average recurrenceinterval of large earthquakes[J].Seismology and Geology,21(4):316—323(in Chinese).
闻学泽.1995.活动断裂地震潜势的定量评估[M].北京:地震出版社.1—150.WEN Xue-ze.1995.Quantitative Estimates of Seismic Potential on Active Faults[M].Seismological Press,Beijing.1—150(in Chinese).
闻学泽.1998.时间相依的活动断裂分段地震危险性评估及其问题[J].科学通报,43(14):1457—1466.WEN Xue-ze.1998.Assessment of time-dependent seismic hazards on segments of active fault,and its problems[J].Chinese Science Bulletin,43(14):1457—1466.
张红艳.2006.新疆地区现代构造应力场非均匀性及成因机理分析[D]:[学位论文].北京:中国地震局地壳应力研究所.ZHANG Hong-yan.2006.Research on heterogeneity and dynamic genesis of the present tectonic stress field in Xinjiangarea[D].Master degree thesis.Institute of Crustal Dynamics,CEA,Beijing(in Chinese).
朱金芳.徐锡伟,黄宗林,等.2005.福州市活断层探测与地震危险性评价[M].北京:科学出版社.ZHU Jin-fang,XU Xi-wei,HUANG Zong-lin,et al.2005.Active Faults Exploration and Seismic Hazard Assessment inFuzhou City[M].Science Press,Beijing(in Chinese).
Bai Meixiang.1998.Paleoearthquake activity in Tadzhikistan and Xinjiang,China[J].Inland Earthquake,12(2):161—166.
Cornnel C A.1968.Engineering seismic risk analysis[J].Bull Seism SOC Am,58:1583—1606.
Ellsworth W L.1999.A physically based earthquake recurrence model for estimation of long-term earthquakeprobabilities[R].US Geol Surv Open-File Rept.99—552.
Matthews M V,Ellsworth W L,Reasenberg P A.2002.A Brownian model for recurrent earthquakes[J].Bull SeismSoc Amer,92:2233—2250.
Reid HF.1910.The mechanics of the earthquake,in the California earthquake of April18,1906[A].In:Report ofthe State Earthquake Investigation Commission.Carnegie Institution of Washington Publication87,2.192.
Wells D L and Coppersmith K J.1994.New empirical relationships among magnitude,rupture length,rupture width,rupture area,and surface displacement[J].Seismological Society of America Bulletin,84(4):974—1002.
Working Group on California Earthquake Probabilities.1988.Probabilities of large earthquakes occurring in Californiaon the San Andreas fault[R].US Geol Surv Open-File Rep.88—398.
Working Group on California Earthquake Probabilities.1990.Probabilities of large earthquakes in the San FranciscoBay Region,California[J].US Geol Surv Circ,1053—1103.
Working Group on California Earthquake Probabilities.1995.Seismic hazards in Southern California:probableearthquakes,1994—2024[J].Bull Seis Soc Am,85:379—439.
Working Group on California Earthquake Probabilities.1999.Earthquake probabilities in the San Francisco Bay Region2000—2030:A Summary of findings[R].US Geological Survey Open-File Report.99—517.
Working Group on California Earthquake Probabilities.2003.Earthquake probabilities in the San Francisco Bay Region2002—2031[R].US Geol Surv Open-File Rept.3—214.
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