Abstract: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.
XU Jinjun,GUO Xinwei,ZHANG Hongbo et al. Extraction and Analysis of Variation Characteristics of Ground Tilt at Wenchuan Station[J]. jgg, 2016, 36(3): 270-273.