近震震级测定方法研究

A STUDY ON THE METHODS FOR DETERMINING LOCAL MAGNITUDES OF EARTHQUAKES

  • 摘要: 本文根据北京电信传输地震台网在1978-1984年期间的395次地震1.0ML6.2;10△600km资料,讨论了近震震级 ML 的量规函数、台基校正、仪器分量校正和震源区校正等,并着重研究了信号持续时间震级 MD 的不同测定方法和误差.结果表明,如果采用本文中所述的方法,不需添加任何校正值,只用少数几个台甚至仅用一个台的资料就可逼近无偏震级.必须指出,持续时间震级 MD 在震级大于4.8时可产生震级饱和现象,对此,用另一条具有较大斜率的方程拟合便可得到满意的结果.

     

    Abstract: This paper discusses the calibration function used in the formula for determining local magnitude, ML, of earthquakes and the corrections for station site, instrument component, and the azimuth of the station with respect to the epicenter, on the basis of the data from 395 earthquakes (1.0ML6.2; 10 km△600km) recorded by the Beijing Telemetered Seismic Network during the period of 1978 to 1984. The research also stresses the different methods for the determination of magnitude MD by signal duration and the associated errors. The results indicate that the magnitude estimation can have a higher precision by using the method proposed in this paper. With signal duration data from only a few stations or even a single station, an unbiased estimate of magnitude can be obtained without any additional correction. It must be pointed out that the signal duration magnitude, MD, shows a tendency of saturation when the magnitude is greater than 4.8. In that case satisfactory results may be obtained by using another fitting equation with a greater slope.

     

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