Propagation and arrest of dikes under topography: Models applied to the 2014 Bardarbunga (Iceland) rifting event

International audience Dikes along rift zones propagate laterally downslope for tens of kilometers, often becoming arrested before topographic reliefs. We use analogue and numerical models to test the conditions controlling the lateral propagation and arrest of dikes, exploring the presence of a slo...

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Bibliographic Details
Published in:Geophysical Research Letters
Main Authors: Urbani, S., Acocella, V., Rivalta, E., Corbi, F.
Other Authors: Géosciences Montpellier, Institut national des sciences de l'Univers (INSU - CNRS)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA)
Format: Article in Journal/Newspaper
Language:English
Published: HAL CCSD 2017
Subjects:
rifting event
dike propagation
topography
rigidity
stress gradient
Bardarbunga
[SDU]Sciences of the Universe [physics]
Iceland
Online Access:https://hal-insu.archives-ouvertes.fr/insu-03661349
https://hal-insu.archives-ouvertes.fr/insu-03661349/document
https://hal-insu.archives-ouvertes.fr/insu-03661349/file/Geophysical%20Research%20Letters%20-%202017%20-%20Urbani%20-%20Propagation%20and%20arrest%20of%20dikes%20under%20topography%20Models%20applied%20to%20the%202014.pdf
https://doi.org/10.1002/2017GL073130
Description
Summary:International audience Dikes along rift zones propagate laterally downslope for tens of kilometers, often becoming arrested before topographic reliefs. We use analogue and numerical models to test the conditions controlling the lateral propagation and arrest of dikes, exploring the presence of a slope in connection with buoyancy and rigidity layering. A gentle downslope assists lateral propagation when combined with an effective barrier to magma ascent, e.g., gelatin stiffness contrasts, while antibuoyancy alone may be insufficient to prevent upward propagation. We also observe that experimental dikes become arrested when reaching a plain before opposite reliefs. Our numerical models show that below the plain the stress field induced by topography hinders further dike propagation. We suggest that lateral dike propagation requires an efficient barrier (rigidity) to upward propagation, assisting antibuoyancy, and a lateral pressure gradient perpendicular to the least compressive stress axis, while dike arrest may be induced by external reliefs.

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