Deviation from power law of the global seismic moment distribution

Isabel Serra,Álvaro Corral

doi:10.1038/srep40045

Isabel Serra, Álvaro Corral

Open Access

https://doi.org/10.1038/srep40045

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Abstract

The distribution of seismic moment is of capital interest to evaluate earthquake hazard, in particular regarding the most extreme events. We make use of likelihood-ratio tests to compare the simple Gutenberg-Richter power-law (PL) distribution with two statistical models that incorporate an exponential tail, the so-called tapered Gutenberg-Richter (Tap) and the truncated gamma, when fitted to the global CMT earthquake catalog. Although the Tap distribution does not introduce any significant improvement of fit respect the PL, the truncated gamma does. Simulated samples of this distribution, with parameters β = 0.68 and mc = 9.15 and reshuffled in order to mimic the time occurrence of the order statistics of the empirical data, are able to explain the temporal heterogeneity of global seismicity both before and after the great Sumatra-Andaman earthquake of 2004.

Highlights

The distribution of seismic moment is of capital interest to evaluate earthquake hazard, in particular regarding the most extreme events
In agreement with Bell et al.[23], we find that: (i) the power-law fit can be safely rejected in front of the tapered Gutenberg-Richter (Tap) distribution for any time window ending between 1984 and before 2004; and (ii) the results change drastically after the occurrence of the great 2004 Sumatra earthquake, for which the power law cannot be rejected at the 0.05 level
Testing different statistical models for the distribution of seismic moment of global shallow seismicity we have found that, in contrast to the Tap distribution, the truncated gamma brings significant improvement with respect to the power law

Summary

OPEN Deviation from power law of the global seismic moment distribution

Isabel Serra1 & Álvaro Corral[1,2] received: 08 August 2016 accepted: 30 November 2016. We make use of likelihood-ratio tests to compare the simple Gutenberg-Richter power-law (PL) distribution with two statistical models that incorporate an exponential tail, the so-called tapered Gutenberg-Richter (Tap) and the truncated gamma, when fitted to the global CMT earthquake catalog. Other authors consider the upper truncated power-law distribution[13,26], given by f(M; β, θ) ∝ 1/M1+β for a

Model Comparison

Simulated Data with Temporal Reshuffling

Discussion

Additional Information