title: Coseismic seafloor deformation in the trench region during the Mw8.8 Maule megathrust earthquake.
abstract: The Mw8.8 megathrust earthquake that occurred on 27 February 2010 offshore the Maule region of central Chile triggered a destructive tsunami. Whether the earthquake rupture extended to the shallow part of the plate boundary near the trench remains controversial. The up-dip limit of rupture during large subduction zone earthquakes has important implications for tsunami generation and for the rheological behavior of the sedimentary prism in accretionary margins. However, in general, the slip models derived from tsunami wave modeling and seismological data are poorly constrained by direct seafloor geodetic observations. We difference swath bathymetric data acquired across the trench in 2008, 2011 and 2012 and find ~3-5 m of uplift of the seafloor landward of the deformation front, at the eastern edge of the trench. Modeling suggests this is compatible with slip extending seaward, at least, to within ~6 km of the deformation front. After the Mw9.0 Tohoku-oki earthquake, this result for the Maule earthquake represents only the second time that repeated bathymetric data has been used to detect the deformation following megathrust earthquakes, providing methodological guidelines for this relatively inexpensive way of obtaining seafloor geodetic data across subduction zone.
authors.affiliation: Departamento de Geofísica, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Santiago, Chile.
authors.forename: A
authors.initials: A
authors.lastname: Maksymowicz
authors.affiliation: Scripps Institution of Oceanography, University of California, San Diego, CA, USA.
authors.forename: C D
authors.initials: CD
authors.lastname: Chadwell
authors.affiliation: Departamento de Geofísica, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Santiago, Chile.
authors.forename: J
authors.initials: J
authors.lastname: Ruiz
authors.affiliation: College of Earth, Ocean and Atmospheric Sciences, Oregon State University, Corvallis, OR, USA.
authors.forename: A M
authors.initials: AM
authors.lastname: Tréhu
authors.affiliation: Departamento de Geofísica, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Santiago, Chile.
authors.forename: E
authors.initials: E
authors.lastname: Contreras-Reyes
authors.affiliation: GEOMAR - Helmholtz-Centre for Ocean Research, Kiel, Germany.
authors.forename: W
authors.initials: W
authors.lastname: Weinrebe
authors.affiliation: Escuela de Ciencias del Mar, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile.
authors.forename: J
authors.initials: J
authors.lastname: Díaz-Naveas
authors.affiliation: Lamont-Doherty Earth Observatory, Columbia University, New York, NY, USA.
authors.forename: J C
authors.initials: JC
authors.lastname: Gibson
authors.affiliation: Scripps Institution of Oceanography, University of California, San Diego, CA, USA.
authors.forename: P
authors.initials: P
authors.lastname: Lonsdale
authors.affiliation: Scripps Institution of Oceanography, University of California, San Diego, CA, USA.
authors.forename: M D
authors.initials: MD
authors.lastname: Tryon