用振幅衰减系数和卓越频率衰减系数测定Q值的探讨

ESTIMATES OF Q VALUE USING AMPLITUDES ATTENUA-TION COEFFICIENT AND PREDOMINANT FREQUENCIES ATTENUATION COEFFICIENT OF SMALL LOCAL EARTHQUAKES WAVES

云南地区小震活动频繁,为充分利用这些小震所提供的信息,我们讨论了小震地震波振幅衰减系数和卓越频率衰减系数的变化,并探讨了这两个系数和Q值的关系。

The method of estimating Q value using amplitudes attenuation coefficient K and predominant frequencies attenuation coefficient a of small local earthquakes waves is described, and variation of Q value in process of preparing the Luquan earthquake (Ms = 6.1) on April 18, 1985 are estimated by this method. The results are as follow. The Q value by Dongchuan and Kunming stations are around normal value which are 66 ± 13 and 89 ± 21 respectively from July 1981 to May 1983 and Q value increases from July 1983 till November 1984. The average values of two stations are 275 and 302 respectively in this period.