Postseismic uplift of the Andes following the 2010 Maule earthquake

  • Postseismic surface deformation associated with great subduction earthquakes is controlled by asthenosphere rheology, frictional properties of the fault, and structural complexity. Here by modeling GPS displacements in the 6 years following the 2010 M-w 8.8 Maule earthquake in Chile, we investigate the impact of heterogeneous viscosity distribution in the South American subcontinental asthenosphere on the 3-D postseismic deformation pattern. The observed postseismic deformation is characterized by flexure of the South America plate with peak uplift in the Andean mountain range and subsidence in the hinterland. We find that, at the time scale of observation, over 2 orders of magnitude gradual increase in asthenosphere viscosity from the arc area toward the cratonic hinterland is needed to jointly explain horizontal and vertical displacements. Our findings present an efficient method to estimate spatial variations of viscosity, which clearly improves the fitting to the vertical signal of deformation. Lateral changes in asthenospherePostseismic surface deformation associated with great subduction earthquakes is controlled by asthenosphere rheology, frictional properties of the fault, and structural complexity. Here by modeling GPS displacements in the 6 years following the 2010 M-w 8.8 Maule earthquake in Chile, we investigate the impact of heterogeneous viscosity distribution in the South American subcontinental asthenosphere on the 3-D postseismic deformation pattern. The observed postseismic deformation is characterized by flexure of the South America plate with peak uplift in the Andean mountain range and subsidence in the hinterland. We find that, at the time scale of observation, over 2 orders of magnitude gradual increase in asthenosphere viscosity from the arc area toward the cratonic hinterland is needed to jointly explain horizontal and vertical displacements. Our findings present an efficient method to estimate spatial variations of viscosity, which clearly improves the fitting to the vertical signal of deformation. Lateral changes in asthenosphere viscosity can be correlated with the thermomechanical transition from weak subvolcanic arc mantle to strong subcratonic mantle, thus suggesting a stationary heterogeneous viscosity structure. However, we cannot rule out a transient viscosity structure (e.g., power law rheology) with the short time span of observation.show moreshow less

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Author details:Shaoyang LiORCiD, Marcos Moreno SwittORCiD, Jonathan BedfordORCiDGND, Matthias RosenauORCiDGND, Oliver HeidbachORCiDGND, Daniel MelnickORCiDGND, Onno OnckenORCiDGND
DOI:https://doi.org/10.1002/2016GL071995
ISSN:0094-8276
ISSN:1944-8007
Title of parent work (English):Geophysical research letters
Subtitle (English):Implications for mantle rheology
Publisher:American Geophysical Union
Place of publishing:Washington
Publication type:Article
Language:English
Date of first publication:2017/02/18
Publication year:2017
Release date:2022/06/23
Volume:44
Issue:4
Number of pages:9
First page:1768
Last Page:1776
Organizational units:Mathematisch-Naturwissenschaftliche Fakultät / Institut für Geowissenschaften
DDC classification:5 Naturwissenschaften und Mathematik / 55 Geowissenschaften, Geologie / 550 Geowissenschaften
Peer review:Referiert
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