中国面波震级研究

利用中国现行公式测算的面波震级是个争论已久的问题。本文提出了一些新的看法 ,它在 90°零点严重失控 ,致使震级水平偏高 ,与国际上没有可比性。在地震月报和年报中长期地、大量地、不规范地使用单一水平向记录测报Ms ,这不仅不符合公式定义 ,是一种概念性的失误 ,而且也降低了公式的理论测值。利用中国一类台站实际观测资料 ,并且采用与其他文献不同的方法 ,分三段震中距建立起三个新的计算公式 ,其震级水平与IASPEI标度一致 ,并在均匀程度上有所改善 ,从而能够彻底消除中国面波震级与国际主要地震机构所测面波震级的不协调性

STUDY OF SURFACE- WAVE MAGNITUDE IN CHINA

A large amount of data indicate that the surface - wave magnitude values determined by the BJI formula tend to be higher than those reported by the main international seismological organizations, and there are some other questions. Over the distance ranges of5°～ 20°, 20°～ 160°and 160°～ 180° We used the recent data of the instrument SK records in China and developed three new calculating formulas: Ms = log (Amax/T) + 1.541og△ + 3.53Ms = log (Amax/T) + 1 .731og△ + 3.27and Ms = log (Amax/T) -6.21og△ + 20.6, The three formulas suit the long- period instruments as well. They appear to be completely coincident and link to each other. The magnitude level measured by them agrees with that of the 1ASPEI .scale over most distance ranges. Over the range of 150°～ 160°, the Ms measured by the first formula are lower 0.03 units at 20°and may raise 0.07 tnits in comparison with those measured by the IASPEI formula. Thus this tbrmula would be expected to eliminate the dependence of the determined Ms upon the distances. They will thoroughly eliminate the incoordination of the determined Ms in China with those by the ISC or NEIC.