Possible Origin of Memory in Earthquakes: Real catalogs and ETAS model

TL;DR

This study demonstrates that earthquake records and energy release exhibit memory effects, and the ETAS model can replicate this memory only within specific parameter ranges, aiding in improving earthquake forecasting accuracy.

Contribution

It reveals the presence of memory in seismic data and shows that the ETAS model reproduces this memory only under certain parameter conditions, refining model calibration.

Findings

Memory exists in seismic records and energy release.

ETAS model reproduces earthquake memory within narrow parameters.

Provides constraints for model parameter estimation.

Abstract

Earthquakes are one of the most devastating natural disasters that plague society. A skilled, reliable earthquake forecasting remains the ultimate goal for seismologists. Using the detrended fluctuation analysis (DFA) and conditional probability (CP) methods we find that memory exists not only in inter-occurrence seismic records, but also in released energy as well as in the series of the number of events per unit time. Analysis of the conventional earthquake model (Epidemic Type Aftershock Sequences, ETAS) indicates that earthquake memory can be reproduced only for a narrow range of model's parameters. This finding, therefore provides additional accuracy on the model parameters through tight restrictions on their values in different worldwide regions and can serve as a testbed for existing earthquake forecasting models.