摘要
对青海省玉树结古镇MS7.1级强震的成因及背景进行了分析,并提出灾后重建应该注意的问题。从大地构造背景看,玉树和汶川地震均由印度板块向青藏高原嵌入、引起高原壳-幔物质向东蠕散诱发。正是巴颜喀拉(昆仑)地块向东蠕散,其南侧边界玉树—鲜水河断裂的左行走滑引起了玉树MS7.1级地震。巴颜喀拉(昆仑)地块在向东蠕散的过程中已经经过三次7～8级边界大地震,能量已有较大释放,今后应注意其南部的羌塘—理塘地块向东南的快速蠕散在何处受阻。研究表明,GPS变形不强的地区往往是块体运动受到阻挡、应力集中、能量积蓄的部位,也是最可能引发大震的部位。据此预测昆明以南的玉溪、通海、石屏地区,大理地区,川西盐源、盐塘地区以及雅安、泸定、康定地区(即玉树—鲜水河与龙门山断裂交汇部位),都可能成为阻挡羌塘—理塘地块向东南快速蠕散的应力集中区,应该引起高度注意,加强动态监测,预作防范。
The 2010 Yushu earthquake,originated in Qinghai,struck on April 14,2010,and registered a magnitude of MS 7.1.This paper discusses the origin and background of the earthquake and gives some advices about post-disaster reconstruction.Considering the geotectonic settings,the authors attributes the origin of 2008 Wenchuan earthquake and 2010 Yushu earthquake to the Indian plate＇s wedging in Qinghai-Tibet Plateau,which driving the material of curst-mantle under Qinghai-Tibet Plateau creeping to east and then caused the earthquakes.The Qinghai-Tibet Plateau consists of several different blocks,they were collaged together in Mesozoic and Cenozoic.The movement and collision of these blocks extruded by the Indian plate are the main reasons of those earthquakes around Qinghai-Tibet Plateau in last several years.Just because the eastward movement of Kunlun block leading to the sinistral slip of Yushu-Xianshuihe Fault,then caused the 2010 Yushu earthquake.Until now,the eastward movement of Kunlun block had caused three earthquakes with the magnitude of MS 7 to MS 8,massive accumulated energy had been released.So,the emphasis should be focused on the southeastward moving Qiangtang-Litang block and a strict surveillance must be kept on it.Learned from 2008 Wenchuan earthquake,the region with less movement by GPS always tend to be a center of energy accumulating because the block is resisted by other hard blocks,and is likely to be the region where earthquake will strike.The authors proposed that the following areas could be struck by earthquakes： Yuxi,Tonghai and Shiping areas in the south of Kunming;Dali area;Yanyuan and Yantang areas of western Sichuan Province;Ya＇an,Luding and Kangding areas,which are the cross section of Yushu-Xianshuihe Fault and Longmen Mountain Fault.All of the four areas locate on the frontier of southward arciform thrust-nappe structure zones formed in late Cenozoic,and they likely to be the stress concentration regions when obstructing the movement of Qiangtang-Litang block.High attention with
出处
《地质力学学报》
CSCD
2011年第1期55-63,共9页
Journal of Geomechanics
关键词
玉树地震
成因
GPS变形
Yushu earthquake
origin
GPS deformation
