陕西重力测网起算基准稳定性分析

采用经典平差方法处理重力网数据时,判断起算基准是否稳定是一个关键性问题。本文在精细化处理陕西重力测网观测资料基础上,采用线性回归法,对1992—2011年陕西重力测网起算基准进行了稳定性分析。并以泾阳M_S 4.8地震为例,分析了重力起算基准稳定性对重力网计算的影响及线性回归方法的有效性,结果表明:(1)起算基准重力值随时间变化明显;(2)起算基准扰动影响改正后,地震前后重力场及跨断裂重力段差变化特征更加符合实际情况;(3)处理重力数据及分析重力场变化特征时,必须考虑起算基准稳定性的影响。

Stability analysis of the calculation datum of Shaanxi Gravity Network

When using the classical adjustment method to deal with the data of the gravity network data, it is a key problem to judge whether the calculation datum is stable or not. Based on the fine processing observation data of Shaanxi Gravity Network, we used the linear regression method to analyze the calculation datum stability of Shaanxi Gravity Network between 1992 and 2011. And taking the Jingyang M_S 4.8 earthquake as an example, the effect of stability of gravity on the calculation of gravity network and the validity of the linear regression method are analyzed. The results show that:(1) The initial gravity value of the calculation datum is obviously changed with time; (2) After correcting the value of calculation datum gravity, the variation characteristics of gravity field and gravity segment difference crossing the faults before and after the earthquake is more close to the truth; (3) When dealing with the gravity data and analyzing the characteristics of the gravity field, the influence of the calculation datum stability must be taken into account.