R package ETAS. Modeling Earthquake Data Using ETAS Model. Fits the space-time Epidemic Type Aftershock Sequence (ETAS) model to earthquake catalogs using a stochastic declustering approach. The ETAS model is a spatio-temporal marked point process model and a special case of the Hawkes process. The package is based on a Fortran program by Jiancang Zhuang (available at <>), which is modified and translated into C++ and C such that it can be called from R.