2013年芦山7.0级地震前重力固体潮参数时空变化研究

Temporal and Spatial Variation of Gravity Tide Parameters before the Lushan M7.0 Earthquake in 2013

以2013年芦山7.0级地震为例,探讨重力固体潮参数的时空分布特征与地震孕育的关系。收集分析芦山震区附近17个台站震前2 a的连续重力观测数据,采用VAV调和分析方法分析计算日波和半日波潮汐参数,主要研究半日波M 2波潮汐因子随时间变化的趋势及空间分布情况。结果表明,芦山地震前M 2波潮汐因子趋势变化空间分布大体呈现上升与下降趋势的四象限分布,芦山地震处于四象限中心部位,可能是由震前存在的“闭锁剪力”引起的区域介质变形或密度扰动所致。

In order to investigate the relationship between the temporal and spatial distribution characteristics of gravity tide parameters and earthquake gestation,this paper takes the 2013 Lushan M7.0 earthquake as an example.The continuous gravity observation data of 17 stations in the vicinity of the Lushan earthquake area are collected and analyzed.The parameters of the daily and half-day wave tidal parameters are analyzed by VAV harmonic analysis method.The tidal factors of the half-day M 2 wave are studied with time trend and spatial distribution.The results show that the spatial distribution of the trend of the trend of the M 2 wave tidal factor before the Lushan earthquake generally shows a four-quadrant distribution of rising and falling trends.The Lushan earthquake is at the center of the four quadrants,which may be caused by the“locking shear force”existing before the earthquake deformation or density disturbance.