南天山—帕米尔地区近期重力场动态变化特征

摘要

Using 5 periods of mobile gravity data from 2014 to 2015,we analyzed the gravitational change characteristics of southern Tienshan-Pamir region in the half and one-year scales,and discussed the relationships between seismic activities and gravitational field changes.The result shows that,the half and one-year scales of gravitational changes in southern Tienshan-Pamir region reached (10 ～20) × 10-8 m · s-2 and (20 ～30) × 10-8 m ·s-2 respectively.Gravitational changes show obvious different features in different regions,the Tarim basin shows the positive gravity changes,while the southern Tienshan-Pamir region shows positive and negative gravity changes interactively.Gravitational changes could reflect the gestation and occurrence of strong earthquakes,and the gravity change values increased in epicenter area before earthquake.The gravitational change high gradient zones and gravitational change with zero line occurred in seismogenic zone and its surrounding area,and earthquakes mostly occur in the high positive gradient zones close to the gravitational change zero lines.%利用2014-2016年南天山—帕米尔地区5期流动重力观测资料,分析该地区半年和一年尺度重力变化特征,探讨了地震孕育发生与重力场变化特征的关系.结果表明:南天山一帕米尔地区半年和一年尺度重力变化量分别为(10～20)×10-8 m·s-2和(20 ～30) ×10-8m· s-2,重力场变化有明显的分区特征,塔里木盆地较多表现出重力正值变化,南天山和帕米尔地区正负值变化交替出现.重力场变化能较好地反映该地区地震孕育和发生过程,地震发生前,在震中附近地区的重力变化值出现上升的趋势.在孕震区及附近地区出现重力变化高梯度带,并伴随有重力变化零线,且地震多发生在重力变化正值集中区的零线附近.