@article{ref1,
title="The relevance of foreshocks in earthquake triggering: a statistical study",
journal="Entropy (Basel, Switzerland)",
year="2019",
author="Lippiello, Eugenio and Godano, Cataldo and de Arcangelis, Lucilla",
volume="21",
number="2",
pages="e173-e173",
abstract="An increase of seismic activity is often observed before large earthquakes. Events  responsible for this increase are usually named foreshock and their occurrence  probably represents the most reliable precursory pattern. Many foreshocks  statistical features can be interpreted in terms of the standard  mainshock-to-aftershock triggering process and are recovered in the Epidemic Type  Aftershock Sequence ETAS model. Here we present a statistical study of instrumental  seismic catalogs from four different geographic regions. We focus on some common  features of foreshocks in the four catalogs which cannot be reproduced by the ETAS  model. In particular we find in instrumental catalogs a significantly larger number  of foreshocks than the one predicted by the ETAS model. We show that this foreshock  excess cannot be attributed to catalog incompleteness. We therefore propose a  generalized formulation of the ETAS model, the ETAFS model, which explicitly  includes foreshock occurrence. Statistical features of aftershocks and foreshocks in  the ETAFS model are in very good agreement with instrumental results.<p /> <p>Language: en</p>",
language="en",
issn="1099-4300",
doi="10.3390/e21020173",
url="http://dx.doi.org/10.3390/e21020173"
}