Gambling scores in earthquake prediction analysis

TL;DR

This paper evaluates earthquake prediction methods using gambling scores, showing their dependence on parameters and confirming the nontrivial success of the M8 algorithm, while highlighting the reliability of traditional metrics.

Contribution

It introduces expanded R-characteristics for earthquake prediction analysis and compares their effectiveness to traditional metrics, emphasizing parameter sensitivity.

Findings

Gambling scores depend on alarm weighting and spatial rate accuracy.

M8 prediction of M≥8.0 earthquakes is statistically significant.

Traditional metrics (n, tau) provide more stable significance estimates.

Abstract

The number of successes 'n' and the normalized measure of space-time alarm 'tau' are commonly used to characterize the strength of an earthquake prediction method and the significance of prediction results. To evaluate better the forecaster's skill, it has been recently suggested to use a new characteristic, the gambling score R, which incorporates the difficulty of guessing each target event by using different weights for different alarms. We expand the class of R-characteristics and apply these to the analysis of results of the M8 prediction algorithm. We show that the level of significance 'alfa' strongly depends (1) on the choice of weighting alarm parameters, (2) on the partitioning of the entire alarm volume into component parts, and (3) on the accuracy of the spatial rate of target events, m(dg). These tools are at the disposal of the researcher and can affect the significance estimate in either direction. All the R-statistics discussed here corroborate that the prediction of 8.0<=M<8.5 events by the M8 method is nontrivial. However, conclusions based on traditional characteristics (n,tau) are more reliable owing to two circumstances: 'tau' is stable since it is based on relative values of m(.), and the 'n' statistic enables constructing an upper estimate of 'alfa' taking into account the uncertainty of m(.).