IPOC-Deep: a new seismicity catalog for Northern Chile with >2 million events

Nooshin Najafipour , Christian Sippl , Javad Kasravi, Jonas Folesky, Bernd Schurr

We present a novel seismicity catalog for Northern Chile, which covers 17 years (2007--2023) of data and contains more than 2.2 million events. Raw waveform data from nearly 200 stations including a range of temporary deployments were processed with state-of-the-art algorithms for phase picking (EQTransformer) and association (PyOcto), after which we performed absolute event relocation in a 2.5D velocity model, followed by relative relocation using hypoDD. Events in the catalog are provided with a classification for location quality, determined from properties like gap angle, number of picks and RMS residual, a probabilistic estimate for location uncertainty in horizontal and vertical direction, as well as a classifier for the tectonic unit (plate interface, upper plate, different types of intraslab seismicity).
This article introduces the dataset, which is made accessible to the scientific community and highlights some overall structural features, changes in event numbers, and catalog completeness through time as a consequence of changing station geometries, as well as a zoom into the 2007 Tocopilla earthquake sequence.