汶川台站地倾斜变化特征提取与分析

Extraction and Analysis of Variation Characteristics of Ground Tilt at Wenchuan Station

通过多项式内插、趋势项拟合、快速傅里叶变换以及稳健最小二乘估计,计算观测值对应数学模型的相关参数,利用求解出的数学模型分析地倾斜值的趋势性、周期性以及异常残差。分析认为,地倾斜值呈现趋势性变化的主要原因是内部应力的积累和释放,周期性变化的主要来源是周期性引力和外界的环境条件;连续的倾斜残差异常值出现后,有可能发生地震,且异常值持续时间愈长,地震发生的几率愈高;随着连续异常值的增大,地震的震级会相应提高。

With methods such as polynomial interpolation,trend fitting,fast Fourier transformation and robust least squares estimation,the mathematical model parameters of observations can be calculated.Using this mathematical model,the trend,periodicity and abnormal residuals are analyzed.Through the analysis,conclusions are drawn that the main reason for the change of ground tilt value is the accumulation and release of internal stress,and the cause of cyclical variation is periodic gravitation and external environmental conditions.In addition,there will be some chance of an earthquake after successive residual outliers,and the longer an outlier lasts,the higher the probability of earthquakes.With the increase of continuous outliers,the earthquake magnitude correspondingly increases.