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Innovative Mediterranean ridge seismic experiment

Objective



The Mediterranean Ridge is generally considered to be a prism of sediments scraped off the subducting African plate accreted against the front of the overriding European plate during the process of convergence. IMERSE sets out to study the processes of deformation and fluid expulsion occurring within this
deforming sediment pile and to better delineate the geological boundary between Africa and Europe. The overall objective of IMERSE is to provide the seismic observations necessary for a high resolution structural model for the Western Mediterranean Ridge, for a model of porosity distribution within the wedge, and for an understanding of this accretionary wedge as a
system of interrelated deformation, sediment dewatering, and fluid expulsion.

The IMERSE data set will consist of a combination of
wide-angle and near- vertical reflection data, providing
respectively the velocity and high resolution structural
information required to meet the objectives. These data will be acquired both as profiles across the accretionary wedge of sediments and also within a small area across the deformation front, providing both a two-dimensional section across the
entire system and a three-dimensional data volume in the most critical region. The near-vertical data will be acquired using a large tuned airgun source array, and the wide-angle data
will be acquired by the ocean-bottom seismometers deployed to record the airgun shots.

The data sets will be used to construct a detailed velocity
model for the deforming sediments, using iterative prestack
depth migration on the near- vertical data, and through the
modelling of the wide-angle data. This will subsequently be
inverted for porosity, thus providing information on the
current fluid volume within the deforming sediment pile, and hence by comparison with the undeformed equivalent units, on the fluid expelled from the wedge during accretion and
deformation.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

Christian-Albrechts Universität Kiel
Address
Wischhofstraße 1-3
24148 Kiel
Germany

Participants (7)

Geco Pratla
Norway
Address

4001 Stavanger
Imperial College of Science, Technology and Medicine
United Kingdom
Address
Prince Consort Road
SW7 2BP London
Public Petroleum Corporation AE
Greece
Address
199,Kifissias Avenue
15124 Athens
UNIVERSITY OF BIRMINGHAM
United Kingdom
Address
Edgbaston
B15 2TT Birmingham
Università degli Studi di Trieste
Italy
Address
Via Valerio 10
34127 Trieste
Université de Strasbourg I (Université Louis Pasteur)
France
Address
5 Rue René Descartes
67084 Strasbourg
École Normale Supérieure
France
Address
24 Rue Lhomond
75231 Paris