利用时间域中计算小地震震源参数的方法,求出了京津地区1987年4月至1987年10月间M_L>1.8级21个地震的震源参数,如表1所示。表1中T_r为由地震图中测出的(?)波初动半周期,u_(αm)为(?)波初动振幅,α为求出的震源半径,M_0为地震矩,Δ_σ为应力降。震源半径α是利用参考文献[1]中的T_r-α/v关系曲线,假定Q=400,破裂速度V=2.75公里/秒求出的。由[1]中图2的α/V— Using the method of calculating focal parameters of small earthquakes in time domain, the source parameters of 21 earthquakes with M_L> 1.8 in Beijing-Tianjin region from April 1987 to October 1987 were obtained, as shown in Table 1. In Table 1, T_r is the initial half-cycle of the (?) Wave measured from the seismogram, u_ (αm) is the initial wave amplitude of the wave, α is the radius of the source obtained, M_0 is the seismic moment, and Δ_σ is the stress drop. The source radius α is found using the T_r-α / v relationship in Reference [1] assuming Q = 400 and rupture velocity V = 2.75 km / sec. From [1] in Figure 2 α / V-