陈培善1, 左兆荣1, 肖洪才2. 1988: 用763长周期地震仪台网测定面波震级. 地震学报, 10(1): 11-24.
引用本文: 陈培善1, 左兆荣1, 肖洪才2. 1988: 用763长周期地震仪台网测定面波震级. 地震学报, 10(1): 11-24.
CHEN PEISHANup, ZUO ZHAORONGup, XIAO HONGCAIup2=/. 1988: SURFACE WAVE MAGNITUDE DETERMINED FROM RECORDS 763 LONG PERIOD SEISMOGRAPH NETWORK. Acta Seismologica Sinica, 10(1): 11-24.
Citation: CHEN PEISHANup, ZUO ZHAORONGup, XIAO HONGCAIup2=/. 1988: SURFACE WAVE MAGNITUDE DETERMINED FROM RECORDS 763 LONG PERIOD SEISMOGRAPH NETWORK. Acta Seismologica Sinica, 10(1): 11-24.

用763长周期地震仪台网测定面波震级

SURFACE WAVE MAGNITUDE DETERMINED FROM RECORDS 763 LONG PERIOD SEISMOGRAPH NETWORK

  • 摘要: 根据成层介质中面波的传播理论,考虑到介质的吸收、地球介质与763地震仪所组成的线性滤波器对面波振幅和周期的影响,并假定面波最大振幅对应于Airy相,则可从理论上导出测定面波震级的量规函数为: 763(△)=3.9+0.16(△/TP)+1/3 Ig△+1/2 lg(sin△)+IgTP (1p为Airy相对应的周期。该量规函数在震中距△=20——160范围内,与IASPEI所推荐的量规函数相一致,与实际观测资料在2——178范围內都拟合得很好。 763(△)推广了IASPEI推荐的量规函数使用的震中距和周期范围,这点对我国特别重要,因为发生在中国而又被中国台网记到的地震,震中距大部分在1——20范围内。 用我国763长周期地震仪台网所观测到的垂直向面波最大振幅、周期资料,测定了103个地震的面波震级MS,763,其台网震级误差为0.14,比SK仪台网的(0.20)要小。与NEIS使用世界标准台网测定的真MSZ相比较,发现MS,763与MSZ之间,在统计上无系统差,即△MS=MS,763——MSZ的均值接近于零,而△MS的标准误差为0.21级。

     

    Abstract: The calibration function for surface wave magnitude has been deduced theoretically from surface wave propagation in a layered medium, considering the effect of the linear filter composed of medium absorption, layered earth medium and response of the 763 long period seismograph on the amplitude and period of surface waves: 763(△) =3.9 + 0.16△/Tp + 1/31g△ + l/21g(sin△) + lgTp(1p is period corresponding to Airy phase (i.e. maximum amplitude of surface wave). This calibrating function is consistent with IASPEI(△) recommended by IASPEI at epicentral distance range 20-160 and able to fit quite well with observed data in the broader range 2-178. Extension of epicentral and period ranges for IASPEI(△) has been effected. This case is important for China because most earthquakes occurring in China and recorded by Chinese seismic network are at epicentral distances of 1 -20.The surface wave magnitudes Ms,763 determined in terms of 763(△) for 103 earthquakes recorded by 763 long period seismic network in China have been calculated. The standard deviation is 0.14 magnitude unit, less than that (0.20) measured by median period broadband seismograph (SK) network. In comparison with Msz measured by NEIS using WWSSN, it is shown that there is no systematic difference between Ms,763 and Msz statistically, i.e. the average value of △Ms = Ms,763-Msz, is close to zero (0.009) The standard deviation of △Ms is 0.21.

     

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