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| Titel |
Effect of glacial-interglacial sea-level changes on the displacement and stress field in the forearc and along the plate interface of subduction zones |
| VerfasserIn |
T. Li, A. Hampel |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1869-9510
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| Digitales Dokument |
URL |
| Erschienen |
In: Solid Earth ; 3, no. 1 ; Nr. 3, no. 1 (2012-02-22), S.63-70 |
| Datensatznummer |
250000836
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| Publikation (Nr.) |
 copernicus.org/se-3-63-2012.pdf |
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| Zusammenfassung |
| Combined seismological, space-geodetic and numerical studies have shown that
the seismicity at subduction zones may be modulated by tides and glacier
fluctuations on timescales of 1–100 a, because these changes in loads on
Earth's surface are able to alter the stress field in the upper plate and
along the plate interface. Here we use a two-dimensional finite-element
model of a subduction zone to investigate how glacial-interglacial sea-level
changes affect the forearc region and the plate interface. The model results
show that a sea-level fall by 125 m over 100 ka causes up to 0.7 m of
vertical displacement, with the maximum uplift occurring between the trench
and the coast. The uplift signal induced by the sea-level fall decreases to
zero ~20 km landward of the coastline. A subsequent sea-level rise by
125 m over 20 ka causes subsidence, which is again most pronounced in the
submarine part of the forearc. The sea-level changes cause horizontal
displacements of up to 0.12 m, which are directed seaward during sea-level
fall and landward during sea-level rise. With respect to the stress field,
the sea-level changes lead to variations in the vertical stress and the
shear stress of up to 1.23 MPa and 0.4 MPa, respectively. The shear stress
variations are highest beneath the coast, i.e. in the area where the
sea-level changes cause the strongest flexure. The resulting Coulomb stress
changes on the plate interface are of the order of 0.2–0.5 MPa and indicate
that earthquakes are promoted during sea-level fall and delayed during
sea-level rise. Our findings imply that eustatic sea-level changes during
glacial-interglacial periods may have induced displacements and stress
changes that were large enough to affect the seismic cycle of subduction
thrusts. |
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