An Earthquake Early Warning System for Northern Chile Based on ElarmS-3

Abstract During 2020, the National Seismological Center (CSN) implemented an earthquake early warning system (EEWS) for northern Chile. From a seismological point of view, this area is considered to be one of the largest seismic gaps in Chile, where an Mw∼9.0 earthquake is expected in a region with a population of more than 1.4 million people. From an economical perspective, this region holds 90% of the copper mining companies in Chile, with more than 15% of the Gross National Product coming from the mining industry. Antofagasta Minerals funded an EEWS prototype for this region with the purpose of keeping both the population and the mining industry safe; 25 new seismic stations have been added to the CSN permanent network to develop an EEWS capable of issuing strong shaking alerts, which could potentially save lives and support critical mining operations in the region. During a 20 month period, we successfully detected, located, and calculated the magnitude of 1774 earthquakes (0–300 km depth) using ElarmS-3, an earthquake early warning algorithm from the University of California, Berkeley. The alert time, or the time between when an earthquake alert is issued and the S-wave arrival at the location, is on average ∼24 s, and 96% of shallow and intermediate depth earthquakes (0–150 km) with M ≥5.0 were alerted. We obtained errors of 0.52 ± 0.43 in magnitude, 30.4 ± 42.72 km in location, 43.5 ± 50.0 km in depth, and 6.6 ± 10.6 s in origin time.