title: Subducting seamounts control interplate coupling and seismic rupture in the 2014 Iquique earthquake area.
abstract: To date, the parameters that determine the rupture area of great subduction zone earthquakes remain contentious. On 1 April 2014, the Mw 8.1 Iquique earthquake ruptured a portion of the well-recognized northern Chile seismic gap but left large highly coupled areas un-ruptured. Marine seismic reflection and swath bathymetric data indicate that structural variations in the subducting Nazca Plate control regional-scale plate-coupling variations, and the limited extent of the 2014 earthquake. Several under-thrusting seamounts correlate to the southward and up-dip arrest of seismic rupture during the 2014 Iquique earthquake, thus supporting a causal link. By fracturing of the overriding plate, the subducting seamounts are likely further responsible for reduced plate-coupling in the shallow subduction zone and in a lowly coupled region around 20.5°S. Our data support that structural variations in the lower plate influence coupling and seismic rupture offshore Northern Chile, whereas the structure of the upper plate plays a minor role.
authors.affiliation: GEOMAR Helmholtz Centre for Ocean Research Kiel, Wischhofstrasse 1-3, 24148 Kiel, Germany.
authors.forename: Jacob
authors.initials: J
authors.lastname: Geersen
authors.affiliation: Barcelona Center for Subsurface Imaging, Instituto de Ciencias del Mar, ICREA at CSIC, Passeig Marítim de la Barceloneta 37-49, 08003 Barcelona, Spain.
authors.forename: César R
authors.initials: CR
authors.lastname: Ranero
authors.affiliation: Bundesanstalt für Geowissenschaften und Rohstoffe (BGR), Stilleweg 2, 30655 Hannover, Germany.
authors.forename: Udo
authors.initials: U
authors.lastname: Barckhausen
authors.affiliation: Bundesanstalt für Geowissenschaften und Rohstoffe (BGR), Stilleweg 2, 30655 Hannover, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Reichert