【摘要】 青藏高原东缘地处南北地震带,在卫星自由空气重力异常图上对应明显的正负异常梯级带变化特征,沿着异常梯级带分布多条深大断裂,属于构造单元的边界区域.本文利用重力导纳分析方法,计算了该区重力导纳模型均衡异常背景场;通过与Airy模型和弹性板模型的均衡重力异常特征对比,结合地震活动性分布特点,评价均衡重力异常计算结果和选择计算参数;在此基础上,对比和分析了横跨青藏高原东缘边界南北三条剖面上的均衡异常响应特征;以此均衡重力背景场为参考,进一步解释了1998～2005年流动重力观测得到的重力异常场的时空变化特点.研究结果表明:导纳模型均衡异常更适用于构造边界等反均衡作用区,可反映壳内介质的横向不均衡分布特征.更多还原

【Abstract】 Eastern margin of Tibetan plateau belongs to north-south seismic belt.There is a distinct variation characteristic of gradient zone of positive and negative anomaly on satellite anomaly figure of free air gravity.Along the anomaly zone,there are many deep faults.The eastern margin is also a boundary region of tectonic units.In this paper,we used the gravitational admittance theory and method to compute the background isostasy anomaly of gravitational admittance model in this region.Through comparing the isostasy anomaly characteristics of Airy model and elastic plate model and analyzing the regional seismic activity,we evaluated the results and optimized the parameter used for calculation.Based on this,we finished the comparison and analysis of isostasy anomaly response characteristics along three profiles across the eastern margin of Tibetan plateau,and taking this isostasy anomaly background as the reference field,further explained the temporal and spatial features of mobile gravity measurement dataset of 1998～2005.更多还原