title: Continuing megathrust earthquake potential in Chile after the 2014 Iquique earthquake.
abstract: The seismic gap theory identifies regions of elevated hazard based on a lack of recent seismicity in comparison with other portions of a fault. It has successfully explained past earthquakes (see, for example, ref. 2) and is useful for qualitatively describing where large earthquakes might occur. A large earthquake had been expected in the subduction zone adjacent to northern Chile, which had not ruptured in a megathrust earthquake since a M ∼8.8 event in 1877. On 1 April 2014 a M 8.2 earthquake occurred within this seismic gap. Here we present an assessment of the seismotectonics of the March-April 2014 Iquique sequence, including analyses of earthquake relocations, moment tensors, finite fault models, moment deficit calculations and cumulative Coulomb stress transfer. This ensemble of information allows us to place the sequence within the context of regional seismicity and to identify areas of remaining and/or elevated hazard. Our results constrain the size and spatial extent of rupture, and indicate that this was not the earthquake that had been anticipated. Significant sections of the northern Chile subduction zone have not ruptured in almost 150 years, so it is likely that future megathrust earthquakes will occur to the south and potentially to the north of the 2014 Iquique sequence.
authors.affiliation: National Earthquake Information Center, United States Geological Survey, Golden, Colorado 80401, USA.
authors.forename: Gavin P
authors.initials: GP
authors.lastname: Hayes
authors.affiliation: Department of Geosciences, Pennsylvania State University, University Park, Pennsylvania 16802, USA.
authors.forename: Matthew W
authors.initials: MW
authors.lastname: Herman
authors.affiliation: National Earthquake Information Center, United States Geological Survey, Golden, Colorado 80401, USA.
authors.forename: William D
authors.initials: WD
authors.lastname: Barnhart
authors.affiliation: Department of Geosciences, Pennsylvania State University, University Park, Pennsylvania 16802, USA.
authors.forename: Kevin P
authors.initials: KP
authors.lastname: Furlong
authors.affiliation: Centro Sismológico Nacional, Universidad de Chile, Blanco Encalada 2002, Santiago 8370449, Chile.
authors.forename: Sebástian
authors.initials: S
authors.lastname: Riquelme
authors.affiliation: National Earthquake Information Center, United States Geological Survey, Golden, Colorado 80401, USA.
authors.forename: Harley M
authors.initials: HM
authors.lastname: Benz
authors.affiliation: Global Seismological Services, Golden, Colorado 80401, USA.
authors.forename: Eric
authors.initials: E
authors.lastname: Bergman
authors.affiliation: Centro Sismológico Nacional, Universidad de Chile, Blanco Encalada 2002, Santiago 8370449, Chile.
authors.forename: Sergio
authors.initials: S
authors.lastname: Barrientos
authors.affiliation: National Earthquake Information Center, United States Geological Survey, Golden, Colorado 80401, USA.
authors.forename: Paul S
authors.initials: PS
authors.lastname: Earle
authors.affiliation: Canada Centre for Mapping and Earth Observation, Natural Resources Canada, Ottawa, Ontario K1A 0E4, Canada.
authors.forename: Sergey
authors.initials: S
authors.lastname: Samsonov