地震前后唐山地震台地形变数据频谱特征分析

Autoregression and Spectrum Analysis of Tangshan Deformation Data before and after Earthquakes

该文以唐山地震台1984年以来的地形变数据为研究对象，对其用自回归模型分析后，采用Daniell滑动窗得到其频谱。通过唐山地方震（M1≥5．0）与华北强震（M1≥6．0）前后自回归阶数变化的对比，表明基线的自回归阶数在震前较大，震后变小。水准数据除了在1995年唐山地震的例子中，也有类似的特征。频谱分析也表明，唐山地震台形变数据中反映的周期在2～11天之间。震前的谱成分多于震后的谱成分，基线的频谱变化较水准的频谱变化显著。

Ab Based on the Tangshan deformation data since 1984, the autoregression （AR） model and spectrum analysis with Daniell moving windows are applied. The order of AR model is compared around the time of Tangshan local earthquakes （M1≥5. 0）and strong earthquakes in North China（M1≥6.0）. The result shows that the orders based on the a- nalysis on baseline data are larger before the earthquakes than those after the earthquakes. So are the orders based on the analysis on leveling data excepting the 1995 Tangshan earthquake. The spectrum analysis shows that the main spectrum is about 2~11 days and the spectrum is more plentiful before earthquakes than that after earthquakes. The variation is clearer in baseline spectrum than in the leveling one. However, the yearly spectrum is unclear in the spectrum analysis, which needs further study.