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| Titel |
Shear-wave velocity anomalies in Southern Andes within latitudes 35∘S and 37∘S: model and interpretations from seismic ambient noise |
| VerfasserIn |
Diego M. González Vidal, Anne Obermann, Klaus Bataille, Stephen A. Miller, Matteo Lupi |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250146795
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| Publikation (Nr.) |
 EGU/EGU2017-10839.pdf |
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| Zusammenfassung |
| The volcanic arc of the Southern Andes is linked to the oblique convergence of Nazca
plate beneath the South American plate (subduction velocity of ∼ 66 mm/yr). The
volcanic arc accounts for about sixty active volcanoes of Pleistocene-to-Holocene
ages.
Here we present a regional-scale (i.e. 35∘S and 37.5∘S) Rayleigh surface-wave
tomography from seismic ambient noise that highligths the three-dimensional shear-wave
velocity structure at crustal depths. This study is, to the best of our knowledge, the first
attempt of a regional-scale Ambient Noise Tomography of a volcanic arc. We find that
velocity anomalies are in agreement with the geological setting and the spatial distribution of
the present-day volcanoes. The crystalline Cenozoic basement, represented by the outcrop of
Mio-Pliocene plutons shows high-velocity anomalies greater than 3%. On the other
hand, Descabezado Grande, Puelche and Laguna del Maule volcanic fields show
low-velocity anomalies ranging within 3 − 6% located at 5 − 10 km depth. Nevados de
Longaví, Chillán and Antuco volcanoes also show strong low-velocity anomalies. We
interpret that mid-crustal low-velocity anomalies are associated with a mechanically
weakeaned regions, due to a high porous crust or, the presence of fluids and thermal
anomalies. |
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