A repeating earthquake catalog for Northern Chile

Repeating earthquakes are nearly identical seismic events that are assumed to occur reiteratively on the same fault-patch with highly consistent focal mechanisms. Their magnitude-dependent recurrence intervals can be used to estimate local fault-slip and to infer spatial and temporal patterns of aseismically creeping zones at depth. We construct here the first long-term repeating earthquake catalog for Northern Chile. Using waveforms for 180,000 earthquakes from a recent regional seismicity catalog as templates, a GPU-based template matching is performed to search for repeating earthquakes in the continuous, multiannual seismological data of the permanent IPOC station network between 2006 and 2024. The resulting repeater catalog contains 10,684 events grouped into 3153 families. We observe a notable variability of size and behavior of the families, ranging from long-lasting, regular sequences to short-term, burst-type repeaters. Two megathrust earthquakes in 2007 and 2014 have a strong effect on the spatio-temporal distribution of repeaters. We compute the first time-dependent slip map for the interface between the subducting Nazca slab and the overriding South American plate.The catalog facilitates future detailed analysis of rupture processes, source structures and the spatio-temporal evolution of slow slip at depth. It also allows for comparative studies with other subduction zones, such as Japan.