南美板块的运动和活动形变  

Motion and Active Deformation of South America Plate

作　　者：金双根[1] 朱文耀[1] 

机构地区：[1]中国科学院上海天文台,上海市南丹路80号200030

出　　处：《武汉大学学报（信息科学版）》2002年第4期358-362,共5页Geomatics and Information Science of Wuhan University

基　　金：国家攀登计划资助项目 (970 2 3 10 0 3 ) ;国家"973"计划资助项目 (G19980 40 70 3 );中科院重要基础研究资助项目 (KJ95 1_1_3 0 4) ;上海科技基础发展基金资助项目 (JC14 0 12 )

摘　　要：利用GPS测量南美板块地表位移来研究南美板块的运动和形变以及在智利海沟处纳兹卡_南美边界形变。南美板块以平均 14 .0mm/a的速度整体向北移动 ,在东西向以 10 .9mm/a的速度收缩 ,并存在 3.8mm/a整体性向东偏移 ,因此大西洋在扩张的同时有一个微小的向东移动 ,形成现今大西洋中脊向东扭曲的形态。并基于空间大地测量资料 ,确立独立于任何板块运动模型约束和假设的南美板块欧拉参数 。The South America plate lies among the Caribbean Sea,Peru_Chile sea gouge,Nazca,COCO plate and Atlantic,which subjects to the eastward violent push of Nazca and extrusion of seafloor spreading at mid_Atlantic ridge,especially the second highest mountain Andes,where the tectonic plate activities,such as earthquakes,volcanic eruption,mountain building and other events,take place frequently,so the inter_plate deformation and plate motion are very complicated.Now it provides a guarantee for studying plate motion at an mm/a level with the rapid development of the space geodetic techniques,such as very long baseline interferometry (VLBI),satellite laser range (SLR),global positioning system (GPS) and doppler orbit determination and Radio positioning Integrated by satellite (DORIS) in twenty years.In this paper,by analyzing the plate motion,active deformation of the South America plate,and relative deformation of the Nazca_South America plate through space geodetic measurements,the South America plate is moving northward at average 14.0mm/a,shrinking west eastward at 10.9 mm/a and wholly moving eastward at 3.8 mm/a,so the mid_Atlantic ridge is moving eastward slightly while spreading,which is perhaps the reason that causes mid_Atlantic ridge at about 0～10°S to distort eastward.And this paper further analyzes the present_day plate motion and active deformation of the South America plate based on the Euler vector of the South America plate determined from an about 20_year time span of space geodetic data,incorporating the space geodetic velocity field that was free of any additional tectonic plate model assumption,so the Euler vector of the South America plate derived from space geodetic data can better describe contemporary features of the South America plate motion than the geological model NNR_NUVEL1A that was determined based on the geological and geophysical data in several million years.But the differences of deformation in the South America plate based on these two models are very significant for contemporary cr

关 键 词：南美板块 板块运动 活动形变 欧拉参数 空间大地测量 

分 类 号：P542[天文地球—构造地质学]