Normalization of seismic quantities and units

Abstract

In the seismological field, attention paid to the problem concerning the normalization of seismic quantities and their units has not been enough all along. In different countries, different seismological organizations and different academic periodicals, seismic quantities and their units are used according to different rules and are expressed in different forms. Some of such examples include that some units unapproved by the International Conference on (CGPM) and some units that can not be used simultaneously with SI units according to the stipulation of international standards: such as dyn, erg, and so on, are used; that the symbols of quantities are expressed with wholly regular or wholly italic letters: such as Ms, ML, or Vsl4, Vsz; that the abandoned symbols of measuring units: such as sec, yr, ppm, and so on, are used; that the forms of expressing quantities and units in figures and tables are diversified: such as "quantity [unit]", "quantity (unit)", "quantity, unit", and so on; that the longitude and latitude are expressed as °N and °E, and so on; and that the value range is not expressed in accordance with the algebraic rule: such as 450-550 km, 450 to 550 km, and so on. These non-normalized forms of expression are inconsistent with those forms of expression recommended in the International Standard ISO 31-1992, Quantities and Units. It would be less influential if these expressions are used in a unified way only in a certain country, a certain organization or a certain academic periodical. However, if these seismic quantities and units are used popularly in the global range, negative effects on the international academic exchange and information exchange would be caused. In China, the legal measuring units were put into effect in 1984. Since then, the use of seismic quantities and units has basically followed the mandatory national standard Quantities and Units. The illegal measuring units were basically rejected and the forms of expression have become consistent gradually. But, no unified expressions of and necessary restrictions on seismic quantities and units have been formed so far. Furthermore, there are the effects of diversified expressions of seismic quantities and units in the world and there exist differences in understanding the related stipulations in the national standard. For these reasons, there are still some problems about the use of seismic quantities and units in China. To solve these problems, normalization is necessary. Taking the quantities and units used for seismic parameters as an example, this paper studies and analyzes the following problems: normalization of the quantity names for special use in seismology, normalization of the quantity symbols for special use in seismology, and improper use of measuring units.