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本文利用世界数字化台网(GDSN)的记录资料,分析计算了1981年1月23日道孚、1985年8月23日新疆以及1981年1月18日日本本州等七个发生在不同构造区的大地震在1—10秒周期下的源谱(ω);汇集了本文作者用相同方法计算得到的发生在消减带、活动板块边界及板块内部不同地区大震的另外31个矩震级M_W≥6.4的源谱(ω)及由P波最大振幅求出的体波震级。将新疆及道孚地震与消减带相同矩震级地震的平均源谱相比,其M(ω)值在10秒周期下与其差别不大,而在1—2秒周期下前二者的(ω)值则高出2—3倍。这一结果相当于应力降高3—5倍。 本文计算出了上述消减带和板内地震在0.1到1Hz的频率范围内的log(ω)-longω的斜率平均值分别为-1.69和-1.26。由此值及10秒周期下的(ω)平均值,可估算出消减带及板内地震在上述频率内不同矩震级M_W下的源谱振幅值(ω)。 通过对25个倾滑型地震在周期T=1.43秒下的源谱振幅和体波震级进行最小二乘回归计算得出:log=0.91m_b+11.60,式中的单位为N·m。对走滑型地震m_b的修订后,得出中国板内走滑型地震的经验公式为log=0.91+11.87。
Based on the recorded data from World Digital Network (GDSN), this paper analyzes and evaluates the data of seven sites in different tectonic areas such as Daofu on January 23, 1981, Xinjiang on August 23, 1985, and Honshu on January 18, 1981. The source spectrum (ω) of a large earthquake with a period of 1-10 seconds is a compilation of the other 31 moment magnitudes M_W≥6.4, calculated by the author using the same method and occurring in the abatement zone, the boundary of the active plate and in different areas within the plate The source spectrum (ω) and the bulk wave amplitude obtained from the maximum amplitude of P wave. Compared with the average source spectrum of earthquakes of the same moment magnitude in the earthquakes and abatement zones of Xinjiang and Daofu, the M (ω) values are not significantly different from those of the earthquakes of the same magnitude in the 10-second period. However, the ω ) Value is 2-3 times higher. This result is equivalent to 3-5 times lower stress. The average slope of log (ω) -longω in the frequency range from 0.1 to 1 Hz for the above mentioned attenuation and in-plane earthquakes is calculated to be -1.69 and -1.26, respectively. From this value and the average value of (ω) over a period of 10 seconds, the amplitude (ω) of the source spectrum at different moment magnitudes M_W within the above mentioned frequencies can be estimated. The least-squares regression of the source spectral amplitudes and body-wave amplitudes of 25 sloping earthquakes at a period of T = 1.43 seconds yields: log = 0.91m_b + 11.60 where Nm. After the revision of the strike-slip earthquake m_b, the empirical formula of the strike-slip earthquake in China is log = 0.91 + 11.87.