Testing earthquake prediction algorithms: statistically significant advance prediction of the largest earthquakes in the Circum-Pacific, 1992-1997

Algorithms M8 and MSc (i.e., the Mendocino Scenario) were used in a real-ti me intermediate-term research prediction of the strongest earthquakes in th e Circum-Pacific seismic belt. Predictions are made by M8 first. Then, the areas of alarm are reduced by MSc at the cost that some earthquakes are mis sed in the second approximation of prediction. In 1992-1997, five earthquak es of magnitude 8 and above occurred in the test area: all of them were pre dicted by M8 and MSc identified correctly the locations of four of them. Th e space-time volume of the alarms is 36% and 18%, correspondingly, when est imated with a normalized product measure of empirical distribution of epice nters and uniform time. The statistical significance of the achieved result s is beyond 99% both for M8 and MSc. For magnitude 7.5 +, 10 out of 19 eart hquakes were predicted by Ms in 40% and five were predicted by M8-MSc in 13 % of the total volume considered. This implies a significance level of 81% for M8 and 92% for M8-MSc. The lower significance levels might result from a global change in seismic regime in 1993-1996, when the rate of the larges t events has doubled and all of them become exclusively normal or reversed faults. The predictions are fully reproducible; the algorithms M8 and MSc i n complete formal definitions were published before we started our experime nt [Keilis-Borok, V.I., Kossobokov, V.G., 1990. Premonitory activation of s eismic flow: Algorithm M8, Phys. Earth and Planet. Inter. 61, 73-83; Kossob okov, V.G., Keilis-Borok, V.I., Smith, S.W., 1990. Localization of intermed iate-term earthquake prediction, J. Geophys. Res., 95, 19763-19772; Healy, J.H., Kossobokov, V.G., Dewey, J.W., 1992. A test to evaluate the earthquak e prediction algorithm, M8. U.S. Geol. Surv. OFR 92-401]. M8 is available f rom the IASPEI Software Library [Healy, J.H., Keilis-Borok, V.I., Lee, W.H. K. (Eds:), 1997. Algorithms for Earthquake Statistics and Prediction, Vol. 6. IASPEI Software Library]. (C) 1999 Elsevier Science B.V. All rights rese rved.