昆仑山8.1级地震对川滇地区地壳水平形变的影响
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摘要
为了从整体上(较大尺度)跟踪区域应变场的时空变化,并更客观地描述区域运动场,文中在区域无旋转的基础上使用了以提取中低频应变信息为主的连续非线性应变模型。根据《中国地壳运动观测网络》位于川滇地区GPS测站所产生的复测资料(1999年~2001年~2004年),以1999年~2001年的运动为基本参考(阶段性形变背景),从2001年和2004年两期资料中分离出了2001年昆仑山8.1级地震对其产生的主要影响量。结果表明:①昆仑山8.1级地震对川滇地区产生了可识别的影响,且形变的方式与形变背景既有一定的相似性又有一定差异;②震前运动场非常有序;震后的位移场有序与杂乱并存,GPS测站的位移量一般为数毫米;③震前的主应变场基本为近东西向显张性、南北向显压性,且以张性为优势;震后四川地区基本上为东西向压、南北向张,且以压性为优势,云南地区北东向张、北西向压,且以张性为优势;④震前面应变以膨胀为主,收缩区基本位于川滇块体的东界及附近地区;震后四川地区为面收缩地区(越往北越大),南部为面膨胀地区。从整体上看,昆仑山8.1级地震对川滇地区能量的积累有积极作用,重点应注意西昌-东川段及附近地区。
The Effect of Kunlun Mountains M_S8.1 Earthquake to Curstal Horizontal Deformation in the Sichuan and Yunnan Areas
<br> <Author>Yang Guohua 1)Jiang Zaiseng 2)Zhang Fengshuang 1)Liu Xia 1)Han Yueping 1)Shen Wuchun 1)Wang Li 1)1)First Crust Monitoring and Application Center,CEA,Tianjin 300180,China2)Institute of Earthquake Science,CEA,Beijing 100036,China
<br> In order to track the space-time variation of region strain field on the whole(in large scale),and describe the region movement field more objective,on the basis of region with no rotation,the paper uses nonlinear continuous strain model focused on extracting medium-low frequency strain information.By use of the remeasured GPS data(1999～2001～2004)come from GPS monitoring stations in the Sichuan and Yunnan Areas in the Project of “China Crust Movement Measuring Network”,and in basic reference to movement of 1999～2001(stage deformation setting),we separate the main influencing fact of Kunlun Mountains M_S8.1 earthquake in 2001 from the data of 2001 and 2004,the result suggests:Firstly,the Kunlun Mountains M_S8.1 earthquake produce discriminating effect to the Sichuan and Yunnan Areas,at the same time,the deformation mode and setting have not only certain similitude but also some diversity;Secondly,the movement field before earthquake is very ordinal,but the displacement field after earthquake is ordinal as well as unorderly;The displacement amounts of GPS monitoring stations don't go beyond 10mm generally;Thirdly,the main strain field before earthquake is basically extensive in the approximate EW direction and compressive in a SN direction,and the extension is predominant;the main strain field after earthquake is compressive in a EW direction and extensive in a SN direction in the Sichuan area,and the compression is predominant,in the Yunnan area,it is extensive in a NE direction and compressive in a NW direction,and the extension is predominant;Fourthly,the surface strain before earthquake is dominated by superficial expansion,contractive area located basically in east boundary of the Sichuan and Yunnan block and its neighborhood;after the earthquake,the Sichuan area is surface contractive(the more north,the more great),the south of Sichuan is dominated by superficial expansion.General speaking,the happence of Kunlun Mountains M_S8.1 earthquake acts as a active role in increasing the accumulated energy in the Sichuan and Yunnan Areas.The most important attention must be focused on the section of Xichang-Dongchuan and its neighborhood.
<br> <Keywords>Kunlun Mountains M_S8.1 earthquake Sichuan and Yunnan area GPS Horizontal movement and strain Fatalness of earthquake</div>
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引文
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<div style="padding: 10px 0px 10px 20px;border-top: #ccc 1px solid;background-color: #F7FBFF; text-indent:24px;">陈杰、陈宇坤、丁国瑜等,2003,2001年昆仑山口西MS8.1级地震地表破裂带,第四纪研究,23(6):629～639。
<br> 顾国华、张晶、王武星,2003,关于2001年昆仑山8.1级大地<font color="red">震前</font>后中国大陆水平运动的讨论,地震学报,25(6):653～660。
<br> 江在森、张希、祝意清等,2003,昆仑山西口MS8.1地<font color="red">震前</font>区域构造形变背景,中国科学(D辑),33(增):163～172。
<br> 李延兴、李智、张静华等,2004,中国大陆及周边地区的水平应变场,地球物理学报,47(2):222～231。
<br> 乔学军、王琪、杜瑞林等,2002,昆仑山口西MS8.1级地震的地壳形变特征,大地测量与地球动力学,22(4):6～11。
<br> 任金卫、王敏,2005,GPS观测的2001年昆仑山口西MS8.1级地震地壳形变,第四纪研究,25(1):34～44。
<br> 石耀霖、朱守彪,2006,用GPS位移资料计算应变方法的讨论,大地测量与地球动力学,26(1):1～8。
<br> 杨国华、江在森、武艳强等,2005,中国大陆整体无净旋转基准及其应用,大地测量与地球动力学,25(4):6～10。
<br> 杨国华、江在森、王敏等,2006,印尼地震对我国川滇地区地壳水平活动的影响,大地测量与地球动力学,26(1):9～14。
<br> 中国地震局监测预报司,2002,2001年昆仑山西口8.1级大地震,24～34,北京:地震出版社。</div>
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