川滇地区地壳块体运动特征研究
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摘要
通过对川滇地区块体细划,借助均匀弹性块体应变模型,利用1999~2007年和2009~2011年两个时段GPS观测地壳水平运动场,计算了这两个时间段该区块体应变状态、块体内部均匀弹性变形场及相邻块体边界带的相对运动。考虑汶川地震、玉树地震对该区域的地壳运动的影响,分析计算结果认为:(1)计算结果较好地反映了该区域构造运动特征;(2)川滇地区块体东边界运动主要以走滑为主,安宁河断裂和则木河断裂的交汇部位表现为明显的左旋走滑运动受阻,且其两侧块体应变率积累显著,是未来可能的强震孕育区;(3)2009~2011年与2007~2009年相比,整个区域块体边界运动空间差异增强,可能反映了汶川、玉树地震对该区域地壳运动的影响。
Based on the division of Sichuan-Yunnan area,using the horizontal crustal movement velocity field by GPS measurements during 1999 to 2007 and 2009 to 2011,we calculated the state of block strain,the homogeneous elastic deformation of the internal blocks and relative motion of the boundary between the adjacent blocks by the homogeneous elastic strain block model.Considering the impact of Wenchuan MS8.0 earthquake and Yushu MS7.1 earthquake on crustal movement of Sichuan-Yunnan area,the calculation analysis results showed that:(1) The calculation results reflected the better characteristics of tectonic movement in the region;(2) The movement of the east boundary on Sichuan-yunan block mainly was strike-slip.The intersections of An'ninghe and Zemuhe Faults showed that the left-lateral strike-slip movement was blocked apparently,and there were significant strain accumulation in the block on both sides of this site,which indicated it maybe the area of possible strong earthquakes preparation in the future;(3) The spatial differences of the blocks boundary movement were enhanced in 2009~2011 than that in 2007~2009,which reflects the impact of Wenchuan MS8.0 earthquake and Yushu MS7.1 earthquake on the regional crustal movement in the whole area.
Based on the division of Sichuan-Yunnan area,using the horizontal crustal movement velocity field by GPS measurements during 1999 to 2007 and 2009 to 2011,we calculated the state of block strain,the homogeneous elastic deformation of the internal blocks and relative motion of the boundary between the adjacent blocks by the homogeneous elastic strain block model.Considering the impact of Wenchuan MS8.0 earthquake and Yushu MS7.1 earthquake on crustal movement of Sichuan-Yunnan area,the calculation analysis results showed that:(1) The calculation results reflected the better characteristics of tectonic movement in the region;(2) The movement of the east boundary on Sichuan-yunan block mainly was strike-slip.The intersections of An'ninghe and Zemuhe Faults showed that the left-lateral strike-slip movement was blocked apparently,and there were significant strain accumulation in the block on both sides of this site,which indicated it maybe the area of possible strong earthquakes preparation in the future;(3) The spatial differences of the blocks boundary movement were enhanced in 2009~2011 than that in 2007~2009,which reflects the impact of Wenchuan MS8.0 earthquake and Yushu MS7.1 earthquake on the regional crustal movement in the whole area.
引文
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张希,张四新,王双绪,等.2007.川滇地区近期地壳运动的应变积累[J].大地测量与地球动力学,27(4):8-15.
赵静,江在森,武艳强,等.2011.汶川地震前后川滇块体应变与断裂变形特征研究[J].大地测量与地球动力学,31(5):30-34.
郑文俊,张培震,袁道阳,等.2009.GPS观测及断裂第四纪滑动速率所反映的青藏高原北部变形[J].地球物理学报,52(10):2491-2580.
方颖,江在森,张晶,等.2006.川滇地区断层形变模型与应变积累分析[J].大地测量与地球动力学,26(2):48-52.
李延兴,黄珹,胡新康,等.2001.板内块体的刚性弹塑性运动模型与中国大陆主要块体的应变状态[J].地震学报,23(6):565-572.
吕江宁,沈正康,王敏.2003.川滇地区现代地壳运动速度场和活动块体模型研究[J].地震地质,25(4):543-554.
申重阳,王琪,吴云,等.2002.川滇菱形块体主要边界运动模型的GPS数据反演分析[J].地球物理学报,45(3):352-361.
沈正康,王敏,甘卫军,等.2003.中国大陆现今构造应变率场及其动力学成因研究[J].地学前缘,10(特刊):93-100.
王阎昭,王恩宁,沈正康,等.2008.基于GPS资料约束反演川滇地区主要断裂现今活动速率[J].中国科学(D辑),38(5):582-597.
徐锡伟,张培震,闻学泽,等.2005.川西及其邻近地区活动构造基本特征与强震复发模型[J].地震地质,27(3):448-461.
张希,蒋锋云,崔笃信,等.2011.四川及邻区GPS观测揭示的应变积累与大震影响分析[J].大地测量与地球动力学,31(5):9-13.
张希,张四新,王双绪,等.2007.川滇地区近期地壳运动的应变积累[J].大地测量与地球动力学,27(4):8-15.
赵静,江在森,武艳强,等.2011.汶川地震前后川滇块体应变与断裂变形特征研究[J].大地测量与地球动力学,31(5):30-34.
郑文俊,张培震,袁道阳,等.2009.GPS观测及断裂第四纪滑动速率所反映的青藏高原北部变形[J].地球物理学报,52(10):2491-2580.
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