The 23 December 2004

The 23 December 2004, M8.1 Macquarie Great earthquake, happened outside the areas of the standard M8 application (i.e., the 262 circles of 667-km radius each). The annual rate of earthquakes reported from a CI of the 667-km radius in this region is about 4-6 main shocks per year (which is much smaller than the rate of 20 requested by the standard version of M8 algorithm). As on July 1, 2004 the modified version of M8 aimed at M8.0+ that uses magnitude cutoffs corresponding to the rates of 2 and 4 m.s. per year (instead of 10 and 20) reports TIP in a circle centered at (57.00S, 157.50E), which expires by the end of 2005. The area of this TIP is some 120 km away from the epicenter of the 2004 Great Macquarie earthquake. Thus, in the frames of extended testing of M8 algorithm and its modifications this case history would rather score a failure-to-predict.