云南中北部地区水平形变应变场研究

Research on Horizontal Deformation-strain Field of the Central and Northern Part in Yunnan Province

根据云南地区 1999～ 2 0 0 1年的GPS观测求得的水平形变场和应变场 ,研究了云南北部地区的形变和应变特征。研究表明 ,研究区的中部地壳位移量较小 ,比较稳定 ,西部和东部位移量较大 ,活动性较强。应变场揭示出 ,本区地壳及其各次一级断块的主压应变轴方向都为NW SE方向 ,主张应变轴方向为NE SW向。研究区北部以张应变为主导 ,中部和南部压应变占主导地位。剪应变等值线的展布方向与活动断裂走向基本一致。断层活动的应变应力场与各个断裂带所处的构造位置有关 ,活动性质不尽相同。

Based on a horizontal deformation and strain field obtained from GPS observation in Yunnan Province during 1999～2000, to study the characteristics of deformation and strain at the northern part of Yunnan Province.The results on deformation showed, a displacement magnitude of the central part is smaller and stabler, however, that activity of the western, eastern and southern part is larger and strong, in North Yunnan. The research of the strain field has indicated that a principal axis of compression strain in this region and its second-order blocks is in NW-SE direction, while a principal axis of tensil strain is in NE-SW. There is the predominace of tencile strain for the northern part, but predominace of conpresive strain from the central and southern part. The strain-stress field induced fault activities is related to structure place of the distinct fracture zones, and its active features are a little differences.