中国大陆与香港及周围地区的地震目录完全性分析

地震活动性中心Ｇｕｔｅｎｂｅｒｇ－Ｒｉｃｈｔｅｒ关系（ｌｏｇＮ＝ａ－ｂＭ）在确定地震发生率时起着重要作用，实际分析中存在的对Ｇ－Ｒ关系的偏离主要是由于地震目录的不完全性引起：即在低震级端因地震的监测能力有限，在高震级端因大震的稀少导致的统计涨落。

Completeness Analysis of Earthquake Catalogues of China and Hong Kong and Its Vicinity

The Gutenberg Richter relation (log N=a-bM ) in seismicity analysis is a useful equation in determination of earthquake occurrence rate.Deviations of the G R line from linearity are due to incompleteness of data because of the limited detection threshold of events at small M ,and statistical fluctuations because of the scarcity of events at large M .Based on the instrumental earthquake records in the past 30 years,the G R linear relation has been determined from the Chinese mainland.The relation show a strong stationary over different time and magnitude ranges.Based on the G R relation,we have determined the incompleteness of the historical record.The loss rates have been computed for different time and magnitude ranges.The loss rates obtained from China were then applied to estimate the earthquake occurrence rates of the Hong Kong region.The statistical parameters in the G R relation constructed from the modern instrumental record and the historical record are drastically different.However,when the G R relations were constructed from the earthquake numbers corrected for record loss,the statistical parameters in the G R relation agree well with that obtained from the instrumental record.The incompleteness analysis provides a possible means for obtaining more accurate occurrence rates for areas of low seismicity.