title: Intense foreshocks and a slow slip event preceded the 2014 Iquique Mw 8.1 earthquake.
abstract: The subduction zone in northern Chile is a well-identified seismic gap that last ruptured in 1877. The moment magnitude (Mw) 8.1 Iquique earthquake of 1 April 2014 broke a highly coupled portion of this gap. To understand the seismicity preceding this event, we studied the location and mechanisms of the foreshocks and computed Global Positioning System (GPS) time series at stations located on shore. Seismicity off the coast of Iquique started to increase in January 2014. After 16 March, several Mw > 6 events occurred near the low-coupled zone. These events migrated northward for ~50 kilometers until the 1 April earthquake occurred. On 16 March, on-shore continuous GPS stations detected a westward motion that we model as a slow slip event situated in the same area where the mainshock occurred.
authors: Departamento de Geofísica, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Santiago, Chile. sruiz@dgf.uchile.cl.
authors: S
authors: S
authors: Ruiz
authors: Istituto Nazionale di Geofisica e Vulcanologia, Centro Nazionale Terremoti, Rome, Italy.
authors: M
authors: M
authors: Metois
authors: School of Environmental Sciences, University of Liverpool, Liverpool, UK.
authors: A
authors: A
authors: Fuenzalida
authors: Departamento de Geofísica, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Santiago, Chile.
authors: J
authors: J
authors: Ruiz
authors: Centro Sismológico Nacional, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Santiago, Chile.
authors: F
authors: F
authors: Leyton
authors: Institut de Physique du Globe de Paris, Sorbonne Paris Cité, Université Paris Diderot, UMR 7154 CNRS, Paris, France.
authors: R
authors: R
authors: Grandin
authors: Laboratoire de Geologie, UMR 8538 CNRS Ecole Normale Superieure, Paris, France.
authors: C
authors: C
authors: Vigny
authors: Laboratoire de Geologie, UMR 8538 CNRS Ecole Normale Superieure, Paris, France.
authors: R
authors: R
authors: Madariaga
authors: Departamento de Geofísica, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Santiago, Chile.
authors: J
authors: J
authors: Campos