鄂尔多斯块体周缘地震活动特征分析
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摘要
分析了鄂尔多斯块体周缘的地震活动特征,结果表明块体的东缘、南缘、西缘均发生过8级强震或多次7级以上地震,而北缘历史上仅发生过1次7级地震,可见块体周缘的强震活动水平存在显著差异,中强地震活动的时间、空间差异也较为显著,1929年以前,块体北缘没有中强地震记录,而块体东缘、南缘、西缘却是中强地震的丛集区域,1929年以后,块体周缘的地震活动格局发生了显著变化。2008年5月12日汶川8.0级地震后,多种迹象表明,鄂尔多斯块体北缘特别是西北缘的地震危险趋势将进一步加剧。b值空间扫描结果显示该区域也是低b值高应力积累区域,鄂尔多斯块体北缘的历史中强地震均发生在这些高应力积累的区域。在关注鄂尔多斯块体西北缘的同时,也应特别关注超长平静区内蒙古临河至晋冀蒙交界地区发生强震的可能性。
This paper has analyzed seismic activity characteristics around 0rdos block.The results show that there are MS8 earthquakes or MS≥7.0 earthquakes in eastern edge,southern edge and western edge of Ordos block,but there is only one MS7.0 earthquake in borthern edge,which indicates that there is a marked difference around Ordos block.On the other hand,the difference of spatial and temporal of moderately strong earthquakes is obvious: there is not moderately strong earthquake data in northern edge of the block,but a lot in the eastern,southern and western edges before 1929.There is an obvious change for the seismic activity pattern after 1929.After the MS8.0 earthquake on May 12,2008,the northwest margin of the Ordos block,including Alashanzuoqi,Alashanyouqi of Inner Mongolia and the China-Mongolian border appeared moderate earthquake response situation.A variety of signs show that the northern margin of the Ordos block,especially the northwestern edge,the trend of earthquake risks is further exacerbated.B value space scan results show this region is low b value and high stress accumulation area,where strong earthquakes of the northern margin of the Ordos block occurred.Concerned about the northwestern margin of the Ordos block,while special attention should be paid to the possibility of strong earthquakes of long quiet area from Linhe,Inner Mongolia to Shanxi,Hebei and Inner Mongolia border
This paper has analyzed seismic activity characteristics around 0rdos block.The results show that there are MS8 earthquakes or MS≥7.0 earthquakes in eastern edge,southern edge and western edge of Ordos block,but there is only one MS7.0 earthquake in borthern edge,which indicates that there is a marked difference around Ordos block.On the other hand,the difference of spatial and temporal of moderately strong earthquakes is obvious: there is not moderately strong earthquake data in northern edge of the block,but a lot in the eastern,southern and western edges before 1929.There is an obvious change for the seismic activity pattern after 1929.After the MS8.0 earthquake on May 12,2008,the northwest margin of the Ordos block,including Alashanzuoqi,Alashanyouqi of Inner Mongolia and the China-Mongolian border appeared moderate earthquake response situation.A variety of signs show that the northern margin of the Ordos block,especially the northwestern edge,the trend of earthquake risks is further exacerbated.B value space scan results show this region is low b value and high stress accumulation area,where strong earthquakes of the northern margin of the Ordos block occurred.Concerned about the northwestern margin of the Ordos block,while special attention should be paid to the possibility of strong earthquakes of long quiet area from Linhe,Inner Mongolia to Shanxi,Hebei and Inner Mongolia border
引文
[1]邓起东,尤惠川.鄂尔多斯周缘断陷盆地带的构造话动特征及其形成机制[J].现代地壳运动研究,1985,(1):58-78.
[2]国家地震局鄂尔多斯周缘活动断裂系课题组.鄂尔多斯周缘活动断裂系[M].北京:地震出版社,1988.
[3]邓起东,程绍平,闵伟,等.鄂尔多斯块体新生代构造活动和动力学的讨论[J].地质力学学报,1999,5(3):13-21.
[4]高立新,曹孟娜,张晖.河套带汾渭带中等地震活动平静对中强地震的指示意义[J].西北地震学报,2009,31(4):358-362.
[5]Wiemer S and Wyss M.Mapping the frequency-magnitude distribution in asperities:An improvedtechnique to calculate recurrence times[J].J.Geophys.Res.,1997,102(B7):15115-15128.
[6]Wyss M,et al.Mapping asperities by minima of localrecurrence time:San Jacinto-Elsinore fault zones[J].J.Geophys.Res.,2000,105(B4):7829-7844.
[7]易桂喜,范军,闻学泽.由现今地震活动分析鲜水河断裂带中南段活动习性与强震危险地段[J].地震,2005,25(1):58-66.
[8]易桂喜,闻学泽,苏有锦.川滇活动地块东边界强震危险性研究[J].地球物理学报,2008,51(6):1719-1725.
[9]李延兴,张静华,郭良迁,等.鄂尔多斯的逆时针旋转与动力学[J].大地测量与地球动力学,2005,25(3):50-56.
[10]刘杰,郭铁栓,杨立明,等.汶川8.0级地震前地震趋势分析意见的回顾[J].地震,2009,29(1):40-52.
[11]梅世蓉,薛艳,宋治平.汶川8.0级与昆仑山口西8.1级地震前地震活动异常特征与启示[J].地震,2009,29(1):1-14.
[12]刘芳,苗春兰,高艳玲.内蒙古中西部地区尾波Q值研究[J].地震,2007,27(2):72-80.
[13]高立新,孙加林,张晖.中强地震平静是汶川8.0级地震前最显著的地震活动异常[J].地震,2010,30(1):90-97.
[2]国家地震局鄂尔多斯周缘活动断裂系课题组.鄂尔多斯周缘活动断裂系[M].北京:地震出版社,1988.
[3]邓起东,程绍平,闵伟,等.鄂尔多斯块体新生代构造活动和动力学的讨论[J].地质力学学报,1999,5(3):13-21.
[4]高立新,曹孟娜,张晖.河套带汾渭带中等地震活动平静对中强地震的指示意义[J].西北地震学报,2009,31(4):358-362.
[5]Wiemer S and Wyss M.Mapping the frequency-magnitude distribution in asperities:An improvedtechnique to calculate recurrence times[J].J.Geophys.Res.,1997,102(B7):15115-15128.
[6]Wyss M,et al.Mapping asperities by minima of localrecurrence time:San Jacinto-Elsinore fault zones[J].J.Geophys.Res.,2000,105(B4):7829-7844.
[7]易桂喜,范军,闻学泽.由现今地震活动分析鲜水河断裂带中南段活动习性与强震危险地段[J].地震,2005,25(1):58-66.
[8]易桂喜,闻学泽,苏有锦.川滇活动地块东边界强震危险性研究[J].地球物理学报,2008,51(6):1719-1725.
[9]李延兴,张静华,郭良迁,等.鄂尔多斯的逆时针旋转与动力学[J].大地测量与地球动力学,2005,25(3):50-56.
[10]刘杰,郭铁栓,杨立明,等.汶川8.0级地震前地震趋势分析意见的回顾[J].地震,2009,29(1):40-52.
[11]梅世蓉,薛艳,宋治平.汶川8.0级与昆仑山口西8.1级地震前地震活动异常特征与启示[J].地震,2009,29(1):1-14.
[12]刘芳,苗春兰,高艳玲.内蒙古中西部地区尾波Q值研究[J].地震,2007,27(2):72-80.
[13]高立新,孙加林,张晖.中强地震平静是汶川8.0级地震前最显著的地震活动异常[J].地震,2010,30(1):90-97.
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