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| Titel |
Linking the kinematics of the interplate and the offshore morphology along the Chilean subduction margin |
| VerfasserIn |
Isabel Urrutia, Marcos Moreno, Onno Oncken  |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250128664
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| Publikation (Nr.) |
 EGU/EGU2016-8671.pdf |
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| Zusammenfassung |
| Abstract
Morphological features at subduction zones are undoubtedly influenced by the complex
interplay between the subducting slab and the overriding plate. Several studies
suggest that the subduction dynamics is strongly dependent on the geometry and
rheology of the margin (including gravity/density anomalies, viscous mantle flow
and roughness of the slab, among others). However, it is not clear how the
geomorphological variation of the forearc along strike can be used as a proxy
for better understanding the mechanics on the interface and seismotectonic
segmentation. Here we investigate the links between the kinematics of the
plate interface and the morphology of the overriding plate along the Chilean
margin by combining morphometrical and statistical analysis. We constructed
swath profiles subtracting the averaged topography and performed gradient
analysis to characterize variations of morphological features, and we compared
these results with the locking degree distribution derived from the inversion of
GPS data. On the coastal area the bathymetry and topography analysis shows
a planar feature, gently dipping ocean-wards and backed by a cliff, which
exhibits spatial variations in its width, height and extension along-strike. This
morphology suggests a quiescence process or a “stable tectonic condition”,
at least since the late Quaternary (over multiple seismic cycles). The results
indicate that this planar feature spatially correlates with the rupture size of recent
great earthquakes and locking degree areas, suggesting that earthquake cycle
deformation has an imprint on the offshore morphology, which can be used to
study the transfer of stresses among adjacent seismotectonic segments and the
periodicity and location of large earthquakes. In addition, the longevity of this
correlation between topography, earthquake rupture and geodetic locking that likely
integrates over a time window of several 103 to several 105 years indicates that the
instrumentally inferred locking has a long term memory across multiple seismic cycles. |
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