大同─阳高6．1级地震太原台前兆异常

THE PRECURSORY ANOMALIES OBSERVED AT TAIYUAN STATION PRIOR TO DATONG-YANGGAO EARTHQUAKE OF M 6.1

太原台１９８５年至１９９１年的地应力、地倾斜、连通管和地电阻率４种前兆手段的月均值具有明显的正弦形年变规律，且在年变背景上出现年变幅度的增大或减小。前３种手段还叠加有趋势性上升或下降。用差值法定量地消除年变以后，无震时段变化平稳，有震时段异常突出，较好地反映了大同一阳高地区的中强地震。

In this paper,according to the monthly mean-value of the data observed at Taiyuan station from 1985 to 1991 by means of ground stress,ground tilt,water tube tiltmeter and earthresistivity,the study indicated that the mean-values showed sinusoidal annual variation obviously,and the increasing or decreasing of the amplitude of annual variation have appeared,and the annual mean-values of the data except the earth-resistivity showed rising or descending trendly on the background of annual variation.After eliminated guantitatively the annual variation by difference method the data showed stationary variation during nonseismic period,but anomalous variation markdly in the period when the moderate earthquakes occurred in Datong-Yanggao area.