Repeated slope failure linked to fluid migration: the Ana submarine landslide complex, Eivissa Channel, Western Mediterranean Sea.

Berndt, Christian , Costa, S., Canals, M., Camerlenghi, M., De Mol, B. and Saunders, M. (2012) Repeated slope failure linked to fluid migration: the Ana submarine landslide complex, Eivissa Channel, Western Mediterranean Sea. Earth and Planetary Science Letters, 319 . pp. 65-74. DOI 10.1016/j.epsl.2011.11.045.

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Abstract

Submarine slope failures are a well-known geohazard. They are able to destroy seafloor installations along their path and by generating tsunamis they may threaten coastal infrastructures. While the mechanisms involved in submarine landslide generation remain poorly known, there are observations that slope stability can be reduced in the presence of free gas. Here, we present new high-resolution 3D seismic data from the Eivissa Channel between the Iberian Penninsula and the Balearic Promontory in the Western Mediterranean Sea. The data reveal slope stability reduction in this area at least since mid-Quaternary times, and an intimate relationship between fluid migration and slope stability. We show that two landslides, i.e. pre-Ana Slide and Ana Slide, occurred at almost the same location above an erosional channel in the Messinian unconformity. There is seismic evidence that fluids including gas are migrating upwards through this erosional surface and that they charge sedimentary layers at the base of the Ana Slide possibly reducing its strength and predisposing it to failure. Our data show in unprecedented detail the ways in which the presence of gas influences slope stability. The findings illustrate the importance of including high-resolution 3D seismic data in slope stability and tsunami risk assessments to identify shallow gas distribution as one of the main controls on slope stability in gas prone areas.

Document Type: Article
Keywords: slope stability; fluid migration; submarine landslide; 3D seismic imaging; Eivissa Channel; Western Mediterranean Sea; UNDRAINED SHEAR-STRENGTH; ORMEN LANGE AREA; 3D SEISMIC DATA; VALENCIA TROUGH; CONTINENTAL-SLOPE; SALINITY CRISIS; STOREGGA SLIDE; NEW-JERSEY; FLOOR; STABILITY
Research affiliation: OceanRep > GEOMAR > FB4 Dynamics of the Ocean Floor > FB4-GDY Marine Geodynamics
Refereed: Yes
Open Access Journal?: No
Publisher: Elsevier
Projects: HERMIONE, GRACCIE, Future Ocean
Date Deposited: 22 Dec 2011 15:34
Last Modified: 20 Sep 2018 03:47
URI: https://oceanrep.geomar.de/id/eprint/13188

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