北京塔院井水位短临预报指标的研究

STUDY OF THE INDEX OF ANOMALOUS WATER LEVELS IN THE TAYAN WELL,BEIJING WITH RESPECT TO THE SHORT-TERM PREDICTION OF EARTHQUAKES

对塔院井３年水位、气压、固体的逐时值进行一系列数据处理，并用三角多项式拟合以消除年周期影响，把水位日气压系数和水位残差日均方差的余差作为塔院井短临预报指标，改进了水位前兆异常的提取方法。同时用熵的概念对这两个参数做出较客观的评价，计算出它们的前兆效益水平分别达到０．６５和０．５９，说明其较好的反映了地震的前兆信息。

A series of processing of the data obtained from the hourly-measured water levels as well asthe data of the atmosphere-pressure and the earth tide was made. The triangular-pressure fittingwas used to rule out the effect of the annual perieds.Following taking both the factors of the at-mosphere-pressure related water levels and the remaining errors of the mean square errors of thewater level rasiduals as an index for the short-term prediction of earthquakes, it has been im-proved to refine the precursory anomalies of the water level．The concept of“entrophy”has beenadopted to make a relativety objective evaluation of these parameters under question.The effec-tive precusory anomalies may be up to 0．65 and 0. 59，suggesting it is better representative of theprecusory infomation of earthquakes.