大同盆地现今地壳形变及应变分布特征

摘要

Based on the high precision GPS monitoring data from 2006 to 2010 of China Crustal Movement Observation Network,the present crustal three-dimensional velocity fields of Datong basin are obtained.Mainwhile by making use of strain analysis of graphical elements combined with significant test method,the present crustal strain parameters and its distribution features are also obtained,then the tectonic origin of ground fissures in Datong is analyzed.The results show that the present crustal movement of Datong basin demonstrates an overall horizontal extension and internal rift subsidence.The interior basin demonstrates overall tensile strain with the NW-SE direction,the most significant strain is at the northwest of the basin,with its value reaching 1.9 × 10-6/a,and this area is also the typical crack of Datong basin.The ground fissures in Datong basin is controlled by fault activities under the regional tensional stress field with the NW-SN direction.%基于中国地壳运动观测网络工程项目2006-2010年GPS监测成果,获取了大同盆地现今地壳三维形变场,基于此利用图形单元应变分析方法结合参数显著性检验方法,获取了大同盆地现今地壳应变参数及其分布特征,并分析了其与大同市地裂缝群发育的构造成因关系.研究结果表明:大同盆地现今地壳运动呈现出整体水平拉张、内部断陷下沉的发展模式；盆地内部整体以NW-SE向拉张应变为主,以盆地西北部最为显著,量值为1.9×10-6/a,而此区域正是盆地内地裂缝最为发育的地区；盆地内地裂缝为NE向断裂活动所致.