摘要
利用北天山中段最新的流动重力观测数据,通过整理计算平差,绘制该地区半年和一年尺度的重力场变化图像;选取横跨北天山中段乌鲁木齐、独山子两条测线,并分别绘制其重力剖面变化图;结合北天山中段地区动力构造环境,剖析该地区重力变化特征及其与地震孕育之间的关系。分析表明:北天山中段地区重力异常变化值不大,重力变化等值线图和剖面变化图均能较好地反映重力场随时空变化特征;北天山中段动态重力变化特征基本反映了该地区动力构造运动的外部环境;研究区域内的重力场空间格局分布特征较清晰,其重力变化具有明显的分区特征,山体和盆地之间的重力变化具有显著差异,山体与盆地边缘正负重力变化交替出现,且变化相对较平稳。
We analyzed the variation in gravity field in the middle segment of northern Tianshan Mountains in half-and one-year scales by calculating and adjusting the latest mobile gravity observation data.By selecting two lines across Urumqi and Dushanzithe in the middle section of northern Tianshan and plotting the gravity anomaly profiles of these two lines,the relationship between characteristics of gravity anomaly and earthquakes as well as the dynamic tectonic environment of northern Tianshan Mountains were analyzed.The analysis shows that the middle section of northern Tianshan does not exhibit evident anomaly in gravitational distribution,even when the half-or one-year scale of gravitational anomaly images reflect the characteristics of temporal and spatial variations of gravity field in the study area well.Gravity anomaly characteristics of the middle section of northern Tianshan typically reflect the external environment of dynamic tectonic movements,and the different gravity change mechanisms and tectonic environment are closely related.The spatial distribution characteristics of gravity field are clear in the study area,and the gravity field anomalies exhibit obvious zoning features.Clear differences can be seen between mountain and basin areas,and the positive and negative gravity anomaly values typically appear at the mountain and basin edges.Further,the gravity anomaly value is minimal.The gravity profile result shows that the gravity field exhibits an increasing trend in the central part of the northern Tianshan area,thus indicating that the underground substances are under a state of quality loss distribution.The northern Tianshan area that is squeezed between the Tibetan plateau and the Euroasian plate caused the orogenic uplifting of Tianshan,decrease in gravity value,density of crust under the state of quality loss,and the negative gravity value.The Dzungaria Basin in the north slope of northern Tianshan exhibits southward migration and a decreasing trend,with steady increase in crustal substances.The p
出处
《地震工程学报》
CSCD
北大核心
2015年第4期1001-1006,共6页
China Earthquake Engineering Journal
基金
地震科技星火计划(XH14054Y)
国家自然科学基金(41374030
41474016
41274036)
新疆地震科学基金(201410
201411
201412)
关键词
北天山
重力场
重力剖面
构造环境
North Tianshan
gravity field
gravity profile
tectonic environment
