Bayesian confidence intervals for the magnitude of the largest aftershock

Abstract

Aftershock sequences, which follow large earthquakes, last hundreds of days and are characterized by well-defined frequency-magnitude and spatio-temporal distributions. The largest aftershocks in a sequence constitute significant hazard and can inflict additional damage to infrastructure that is already affected by the main shock. Therefore, the estimation of the magnitude of a possible largest aftershock in a sequence is of high importance. In this work, a Bayesian predictive distribution and the corresponding confidence intervals for the magnitude of the largest expected aftershock in a sequence are derived using the framework of Bayesian analysis and extreme value statistics. The analysis is applied to 19 well-known aftershock sequences worldwide to construct retrospectively the confidence intervals for the magnitude of the subsequent largest aftershock by using the statistics of early aftershocks in the sequences. Key Points Constraining the magnitude of the largest aftershock after a damaging mainshockDerivation of Bayesian predictive distribution for large aftershock magnitudesApplication of the method to the past prominent aftershock sequences