中国大陆的垂直形变速率梯度及地震活动
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摘要
在GIS平台上 ,以 195 1～ 1990年中国大陆垂直形变速度图为基础求出的垂直形变速率梯度 ,其变化情况基本上反映了中国大陆地壳的垂直剪应变及相应的剪应力的大小。东部的华北块体垂直形变速率梯度值明显地高于东北和华南地区 ,西部地区的青藏块体和天山地块的梯度较高 ,它们是现代构造活动较强的块体。斜贯中国大陆的察隅 -通化北东向高梯度带和其西侧的银川 -乌丽北东向高梯度带是现代地壳垂直差异活动强烈的地带。现代强震主要孕育发生在高梯度异常区及其附近 ,垂直形变速率梯度异常对地震危险区预测有一定的应用价值。
In this paper we illustrate the gradient of vertical deformation rates, seismotectonics and seismicity in Chinas continent, as well as their relationship. Basing on the map of vertical deformation rate of Chinas continent (1951～1990), we have derived the gradients of vertical deformation rates on a GIS platform. We find that the variation of the gradients reflects basically the magnitudes of vertical crustal shear strain and the corresponding crustal shear stress. In the eastern part of Chinas continent, the gradient of vertical deformation rates of North-China Block is obviously higher than those of Northeast China and South China Blocks. In the western part, the gradients are higher in Qinghai-Tibet and Tianshan Blocks, which are the regions of strong current tectonic activities. The NE-trending Chayu-Tonghua high gradient zone obliquely passes through Chinas continent, and the Yinchuan-Wuli high gradient zone on its west side is the region of intense current vertical differential movement. The current strong earthquakes occur mainly along the anomalous zones with high gradient and their surrounding areas. In the period from 1966 to 1976, most of the strong earthquakes occurred along the NE-trending Chayu-Tonghua high gradient zone, such as the Haicheng M S 7.3, Tangshan M S 7.8, and Xingtai M S 7.2 earthquakes in the northeast section of the zone, and the Songpan M S 7.2, Pingwu M S 7.2, Luhuo M S 7.9, and Longling M S 7.3 earthquakes in the southwest section of the zone. The gradient of vertical deformation rates is a mirror of the vertical crustal shear strain. High gradient zone of vertical deformation rates is therefore the zone of high vertical shear strain, forming the active zone of strong earthquakes. In the western part of China, however, the distribution of strong earthquakes is not accordant completely with the high gradient zone. This is partly because that the leveling data for the western part of China is relatively incomplete, which may cause the lost of information about the vertical deformation rates. In addition, strong earthquake may also be developed in the region where horizontal deformation predominates over vertical deformation. In the evaluation of active tectonics, therefore, an overall consideration should be given to both vertical and horizontal crustal deformations. In a word, the analysis of the gradient of vertical crustal deformation rates has great application potential for the assessment of seismic risk areas.
In this paper we illustrate the gradient of vertical deformation rates, seismotectonics and seismicity in Chinas continent, as well as their relationship. Basing on the map of vertical deformation rate of Chinas continent (1951～1990), we have derived the gradients of vertical deformation rates on a GIS platform. We find that the variation of the gradients reflects basically the magnitudes of vertical crustal shear strain and the corresponding crustal shear stress. In the eastern part of Chinas continent, the gradient of vertical deformation rates of North-China Block is obviously higher than those of Northeast China and South China Blocks. In the western part, the gradients are higher in Qinghai-Tibet and Tianshan Blocks, which are the regions of strong current tectonic activities. The NE-trending Chayu-Tonghua high gradient zone obliquely passes through Chinas continent, and the Yinchuan-Wuli high gradient zone on its west side is the region of intense current vertical differential movement. The current strong earthquakes occur mainly along the anomalous zones with high gradient and their surrounding areas. In the period from 1966 to 1976, most of the strong earthquakes occurred along the NE-trending Chayu-Tonghua high gradient zone, such as the Haicheng M S 7.3, Tangshan M S 7.8, and Xingtai M S 7.2 earthquakes in the northeast section of the zone, and the Songpan M S 7.2, Pingwu M S 7.2, Luhuo M S 7.9, and Longling M S 7.3 earthquakes in the southwest section of the zone. The gradient of vertical deformation rates is a mirror of the vertical crustal shear strain. High gradient zone of vertical deformation rates is therefore the zone of high vertical shear strain, forming the active zone of strong earthquakes. In the western part of China, however, the distribution of strong earthquakes is not accordant completely with the high gradient zone. This is partly because that the leveling data for the western part of China is relatively incomplete, which may cause the lost of information about the vertical deformation rates. In addition, strong earthquake may also be developed in the region where horizontal deformation predominates over vertical deformation. In the evaluation of active tectonics, therefore, an overall consideration should be given to both vertical and horizontal crustal deformations. In a word, the analysis of the gradient of vertical crustal deformation rates has great application potential for the assessment of seismic risk areas.
引文
薄万举,郭良迁.1997.用水准资料计算剪应变公式的推导.地壳形变与地震,17(4):62～66.
BoWanju,GuoLiangqian.1997.Deductionofformulaforcalculatingshearstrainwithlevelingdata.CrustalDeformationandEarthquake,17(4):62～66(inChinese).
郭良迁.1996.北京及周围地区的垂直形变及其速度梯度与地震活动.山西地震,(2):40～43.
GuoLiangqian,1996.VerticaldeformationanditsvelocitygradientandseismicityinBeijinganditsvicinity.EarthquakeRe searchinShanxi,(2):40～43(inChinese).
黄立人,马青,朱文耀,等.1996.高精度GPS测量得到的中国西南地区构造块体运动模型的初步结果.见:李延兴主编.GPS技术研究新进展.天津:天津科学技术出版社.232～229.
HuangLiren,MaQing,ZhuWenyao,etal.1996.PrimaryresultsoftectonicblockmovementmodelforWesternChinade rivedwithhighaccurateGPS .In:LiYanxing,ed.NewdevelopmentforGPStechniquestudy.Tianjin:TianjinScienceandTechnologyPress.232～229(inChinese).
黄秀铭.1994.地变率指标初探.见:国家地震局地质研究所编.现今地球动力学研究及其应用.北京:地震出版社.294～300.
HuangXiuming,1994.Primarystudyoncrustaldeformationrateindex.In:InstituteofGeology,CSB ,ed.Moderngeody namicsresearchanditsapplication.Beijing:SeismologicalPress.294～300(inChinese).
李延兴,胡新康,赵承坤,等.1998.GPS跟踪站观测的初步结果所揭示的板内及板缘地壳水平运动.地壳形变与地震,18(2):28～34.
LiYanxing,HuXinkang,ZhaoChengkun,etal.1998.Intraplateandplate-marginhorizontalcrustaldeformationrevealedbypreliminaryresultsobservedatGPStracingstations.CrustalDeformationandEarthquake,18(2):28～34(inChi nese).
许绍燮.1989.地震预报能力评分.见:国家地震局科技监测司编.地震预报方法使用化研究文集(地震学专业集).北京:学术书刊出版社.586～590.
XuShaoxie,1989.Scoringtheabilityofearthquakeprediction.In:DepartmentofScienceandTechnologyMonitoring,StateSeismologicalBureau,ed.Collectedworksforpracticalresearchonmethodofearthquakeprediction(seismologicalsec tion).
Beijing:ScientificBookandPeriodicalPress.586～590(inChinese).
许绍燮.1973.震兆分析一例.见:《地震战线》编辑部编.地震技术资料汇编.北京:科学技术出版社.20～23.
XuShaoxie.1973.Anexampleofanalysisforearthquakeprecursor.In:EditorialBoardofEarthquakeFront,ed.Collec tionsofseismictechniquedata.Beijing:ScienceandTechnologyPress,20～23(inChinese).
应绍奋,张祖胜,耿士昌,等.1988.中国大陆垂直向现代地壳运动基本特征.中国地震,4(1):1～8.
YingShaofen,ZhangZusheng,GengShichang,etal.1988.BasiccaracteristicsofrecentverticalmovementofChinaMain land.EarthquakeResearchinChina,4(4):1～8(inChinese).
应绍奋,沈永坚,黄立人,等.1997.中国大陆形变场特征及中长期地震危险区划分.见:国家地震局科技发展司编.《中国大陆2005年前强震危险性预测研究》.北京∶地震出版社.163～171.
YingShaofen,ShenYongjian,HuangLiren,etal.1997.ThecharacteristicsofcrustaldeformationfieldofMainlandChinaandzoningmid-longtermearthquakeriskarea.In:DepartmentofScienceandTechnologyDevelopment,StateSeis mologicalBureau,ed.PredictionresearchontheriskofstrongearthquakeinMainlandChinabefore2005.Beijing:SeismologicalPress.163～171(inChinese).
张祖胜.1990.应用大地形变资料估计我国大陆地区近几十年的地震趋势.见:国家地震局分析预报中心编.《中国地震大形势预测研究》.北京:地震出版社.50～65.
ZhangZusheng.1990.EarthquaketrendestimationinMainlandChinainnextdecadeswithgeodeticdata.In:CenterforAnalysisandPrediction,StateSeismologicalBureau,ed.PredictionandresearchesonearthquakesituationinChina.Beijing:SeismologicalPress.50～65(inChinese).
张郢珍,张立人,粟生平,等.1992.中国大陆垂直形变速率梯度与强震危险区.地震地质,14(3):237～244.
ZhangYingzhen,ZhangLiren,SuShengping,etal.1992.Gradientsofverticaldeformationratesandhigh-riskareasofstrongearthquakeinChina.SeismologyandGeology,14(3):237～244(inChinese)
BoWanju,GuoLiangqian.1997.Deductionofformulaforcalculatingshearstrainwithlevelingdata.CrustalDeformationandEarthquake,17(4):62～66(inChinese).
郭良迁.1996.北京及周围地区的垂直形变及其速度梯度与地震活动.山西地震,(2):40～43.
GuoLiangqian,1996.VerticaldeformationanditsvelocitygradientandseismicityinBeijinganditsvicinity.EarthquakeRe searchinShanxi,(2):40～43(inChinese).
黄立人,马青,朱文耀,等.1996.高精度GPS测量得到的中国西南地区构造块体运动模型的初步结果.见:李延兴主编.GPS技术研究新进展.天津:天津科学技术出版社.232～229.
HuangLiren,MaQing,ZhuWenyao,etal.1996.PrimaryresultsoftectonicblockmovementmodelforWesternChinade rivedwithhighaccurateGPS .In:LiYanxing,ed.NewdevelopmentforGPStechniquestudy.Tianjin:TianjinScienceandTechnologyPress.232～229(inChinese).
黄秀铭.1994.地变率指标初探.见:国家地震局地质研究所编.现今地球动力学研究及其应用.北京:地震出版社.294～300.
HuangXiuming,1994.Primarystudyoncrustaldeformationrateindex.In:InstituteofGeology,CSB ,ed.Moderngeody namicsresearchanditsapplication.Beijing:SeismologicalPress.294～300(inChinese).
李延兴,胡新康,赵承坤,等.1998.GPS跟踪站观测的初步结果所揭示的板内及板缘地壳水平运动.地壳形变与地震,18(2):28～34.
LiYanxing,HuXinkang,ZhaoChengkun,etal.1998.Intraplateandplate-marginhorizontalcrustaldeformationrevealedbypreliminaryresultsobservedatGPStracingstations.CrustalDeformationandEarthquake,18(2):28～34(inChi nese).
许绍燮.1989.地震预报能力评分.见:国家地震局科技监测司编.地震预报方法使用化研究文集(地震学专业集).北京:学术书刊出版社.586～590.
XuShaoxie,1989.Scoringtheabilityofearthquakeprediction.In:DepartmentofScienceandTechnologyMonitoring,StateSeismologicalBureau,ed.Collectedworksforpracticalresearchonmethodofearthquakeprediction(seismologicalsec tion).
Beijing:ScientificBookandPeriodicalPress.586～590(inChinese).
许绍燮.1973.震兆分析一例.见:《地震战线》编辑部编.地震技术资料汇编.北京:科学技术出版社.20～23.
XuShaoxie.1973.Anexampleofanalysisforearthquakeprecursor.In:EditorialBoardofEarthquakeFront,ed.Collec tionsofseismictechniquedata.Beijing:ScienceandTechnologyPress,20～23(inChinese).
应绍奋,张祖胜,耿士昌,等.1988.中国大陆垂直向现代地壳运动基本特征.中国地震,4(1):1～8.
YingShaofen,ZhangZusheng,GengShichang,etal.1988.BasiccaracteristicsofrecentverticalmovementofChinaMain land.EarthquakeResearchinChina,4(4):1～8(inChinese).
应绍奋,沈永坚,黄立人,等.1997.中国大陆形变场特征及中长期地震危险区划分.见:国家地震局科技发展司编.《中国大陆2005年前强震危险性预测研究》.北京∶地震出版社.163～171.
YingShaofen,ShenYongjian,HuangLiren,etal.1997.ThecharacteristicsofcrustaldeformationfieldofMainlandChinaandzoningmid-longtermearthquakeriskarea.In:DepartmentofScienceandTechnologyDevelopment,StateSeis mologicalBureau,ed.PredictionresearchontheriskofstrongearthquakeinMainlandChinabefore2005.Beijing:SeismologicalPress.163～171(inChinese).
张祖胜.1990.应用大地形变资料估计我国大陆地区近几十年的地震趋势.见:国家地震局分析预报中心编.《中国地震大形势预测研究》.北京:地震出版社.50～65.
ZhangZusheng.1990.EarthquaketrendestimationinMainlandChinainnextdecadeswithgeodeticdata.In:CenterforAnalysisandPrediction,StateSeismologicalBureau,ed.PredictionandresearchesonearthquakesituationinChina.Beijing:SeismologicalPress.50～65(inChinese).
张郢珍,张立人,粟生平,等.1992.中国大陆垂直形变速率梯度与强震危险区.地震地质,14(3):237～244.
ZhangYingzhen,ZhangLiren,SuShengping,etal.1992.Gradientsofverticaldeformationratesandhigh-riskareasofstrongearthquakeinChina.SeismologyandGeology,14(3):237～244(inChinese)
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