即将通用的矩震级标度Mw──远震震级测定工作综述
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摘要
本文从地震观测数据的利用角度出发，讨论世界范围内远震震级的测定问题。笔者认为，现震级标度存在的弊病是：震级饱和，测值偏差大，过分依赖频率的变动以及需要各种校正等。体波震级的问题大于面波；周期较短的震相问题大于周期较长的震相问题。矩震级标度将逐渐取代依据变幻不定的各种地震波的观用的各种标度。对于远震，长周期地震仪记录的面波震级Ｍｓ将得以发展，成为矩震级的一种辅助标度。本文最后提出了矩震级标度实行后，历史地震震级和区域地震震级如何与之衔接的初步设想。
For the purpose of utilization of earthquake observation data, the problem of magnitude determi-nation of distant earthquakes all over the world is discussed in this paper. In the author's opinion,thecurrently used magnitude scales have the following drawbacks,such as magnitude saturation,signifi-cant differences in determined values,over-reliance on the frequency changes and need of Various cor-rections. The problem of body wave magnitudes is greater than that of surface wave magnitudes,andthe problem of shorter period seismic phases is greater than that of longer period seismic phases.Themoment magnitude scale will gradually replace the currently used various scales which are dependenton various changing seismic waves. Fur distant earthquakes,the surface-wave magnitude(Ms)recorded by long-period seismographs will cuntinue to be used as a supplement to the moment magni-tude scale. Finally,some preliminary thoughts are proposed for bridging over the moment magnitudescale with the historical earthquake magnitudes and regional earthquake magnitudes, after the formeris universally adopted.
For the purpose of utilization of earthquake observation data, the problem of magnitude determi-nation of distant earthquakes all over the world is discussed in this paper. In the author's opinion,thecurrently used magnitude scales have the following drawbacks,such as magnitude saturation,signifi-cant differences in determined values,over-reliance on the frequency changes and need of Various cor-rections. The problem of body wave magnitudes is greater than that of surface wave magnitudes,andthe problem of shorter period seismic phases is greater than that of longer period seismic phases.Themoment magnitude scale will gradually replace the currently used various scales which are dependenton various changing seismic waves. Fur distant earthquakes,the surface-wave magnitude(Ms)recorded by long-period seismographs will cuntinue to be used as a supplement to the moment magni-tude scale. Finally,some preliminary thoughts are proposed for bridging over the moment magnitudescale with the historical earthquake magnitudes and regional earthquake magnitudes, after the formeris universally adopted.
引文
［1］郭履灿、庞明虎，面波震级和它的台基校正值，地震学报，1981年第3卷第3期。［2］Bath，M．，HandbookonEarthquakcMagnitudeDeterminations．Uppsala，1968．［3］Hanks，T．C．andH．kanamori，AMomentMagnitudeSeale，J．G．R．84．B5．2348—2359．1979．［4］USGSNEIC，《PDE》，Jan．，1993．［5］陈培善、白彤霞，震源参数之间的定量关系，地震学报，1991年第13卷第4期。［6］P．雷伯恩，里氏震级标度失势，地震科技情报，1994年第7期。［7］左光荣、吴建平、巫志玲，地幔波震级的规范化标定与观测，地球物理学报，1993年第36卷第5期。
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