Prior to the development of Australian-specific magnitude formulae, the 1935 magnitude correction factors by Charles Richter—originally developed for southern California—were almost exclusively used to calculate earthquake magnitudes throughout Australia prior to the 1990s. Due to the difference in ground-motion attenuation between southern California and much of the Australian continent, many earthquake magnitudes from the early instrumental era are likely to have been overestimated in the Australian earthquake catalogue. A method is developed that adjusts local magnitudes (M_L) using the difference between the original (inappropriate) magnitude formulae (or look-up tables) and the Australian-specific formulae at a distance determined by the nearest recording station likely to have recorded the earthquake. Nationally, these adjustments have reduced the number of earthquakes of M_L ≥ 4.5 in the early instrumental catalogue by approximately 25% since 1900, while the number of M_L ≥ 5.0 earthquakes has reduced by approximately 32% over the same time period. The reduction in the number of moderate-to-large-magnitude earthquakes over the instrumental period yields long-term earthquake rates that are more consistent with present-day rates, since the development of Australian-specific magnitude formulae (approximately 1990). The adjustment of early instrumental magnitudes to obtain consistently derived earthquake catalogue is important for seismic hazard assessments.

在开发澳大利亚特定的震级公式之前，Charles Richter最初为加利福尼亚南部开发的1935年震级校正因子几乎全部用于计算1990年代之前整个澳大利亚的地震震级。由于南加州南部和澳大利亚大陆大部分地区的地震动衰减差异，澳大利亚地震目录中可能会高估了早期仪器时代的许多地震烈度。开发了一种调整局部幅度（M _L）使用原始（不合适的）震级公式（或查询表）与澳大利亚特定公式之间的差值，该距离由可能已记录地震的最近记录台确定。在全国范围内，这些调整具有降低的地震次数中号_大号约25％自1900年以来≥4.5在早期器乐目录，而数量中号_大号≥5.0地震在同一时期内减少了约32％。在仪器化时期中，中到大地震数量的减少产生了长期的地震发生率，这与当今的发生率更加一致，这是因为澳大利亚制定了特定的震级公式（大约1990年）。调整早期仪器震级以获得一致导出的地震目录对于地震危险性评估很重要。