Historical Seismograms - Evidence from the AD 2000 Izu Islands ...

A CATALOGUE OF CHINESEARTHQUAKES (M 2 6.5)FROM 1900 TO 1948 WITH UNIFORM MAGNITUDESDeli ChengJiangsu Provincial Seismological Bureau, ChinaYushou XaeInstitute of Geophysics, State Seismological Bureau, Beijing, ChinaZhifeng DingJiangsu Provincial Seismological Bureau, ChinaABSTRACTAs the magnitude scale, the instrument characteristics, and the measurementmethods are different for different time periods at various seismologicalorganizations, the magnitudes listed in different catalogues ofChinese earthquakes are usually inconsistent. On the basis of collectionand collation of instrumental data for Chinese earthquakes during the period1900 to 1948, the authors revised the calculated magnitudes, giving acatalogue with a uniform magnitude scale. Gutenberg and Richter’s formulasof 1945 and 1956 are used for surface-wave and body-wave magnitudes,respectively. As a supplement, the 1962 Moscow-Prague formula isused to determine magnitudes from short period surface waves. Statisticalresults show that for the period of investigation, the difference betweensurface-wave magnitudes obtained using the two formulas is tolerable.Amplitude and period data from Gutenberg and Richter’s unpublishedoriginal worksheets for Seismicity of the Earth and Associated Phenomenaand all other available sources are used. A calibration curve for theXujiahui (Zi-ka-wei) seismic station is established. An empirical formulais found for estimating magnitude from the maximum recorded distanceof P waves. Regression curves are obtained for magnitudes listed in variouscatalogues relative to our revised magnitudes. Using this data, a newcatalogue is compiled of Chinese earthquakes from 1900 to 1948 with auniform magnitude scale. Only earthquakes with magnitudes M 2 6.5are listed in this paper.Statistical comparison shows that the revised magnitudes for majorearthquakes agree well with those of Abe (1981). Although the mean deviationin the magnitudes listed in the 1983 edition of Catalogue of ChineseEarthquakes [excluding those quoted directly from Hsu Mingtung’s(Xu Mingtong) catalogue] is small, the scatter is rather large.The meaning of the magnitude given in Seismicity of the Earth andAssociated Phenomena is investigated. Our conclusion is consistent withthat of Geller and Kanamori (1977). The seismicity of China and themonitoring of Chinese earthquakes by worldwide seismic stations for theperiod 1900 to 1948 is discussed.Historical Seismogramsand Earthquakes of the World112Copyright C’ 1988 by Academic Press, Inc.All rights of reproduction in any form reserved.