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

Berndt, Christian; Costa, Sergio; Canals, Miquel; Camerlenghi, Angelo; de Mol, Ben; Saunders, Martin. 2012 Repeated slope failure linked to fluid migration: The Ana submarine landslide complex, Eivissa Channel, Western Mediterranean Sea. Earth and Planetary Science Letters, 319-320. 65-74. 10.1016/j.epsl.2011.11.045

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Abstract/Summary

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.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.1016/j.epsl.2011.11.045
Programmes:	NOC Programmes
ISSN:	0012821X
Date made live:	28 Jun 2012 09:41 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/440664

Item Type:

Publication - Article

Digital Object Identifier (DOI):

10.1016/j.epsl.2011.11.045

Programmes:

NOC Programmes

ISSN:

0012821X

Date made live:

28 Jun 2012 09:41 +0 (UTC)

URI:

https://nora.nerc.ac.uk/id/eprint/440664