Since 1995, the most intensive mapping of
the seafloor off the Spanish coast has been
carried out in the framework of the Spanish
Exclusive Economic Zone Project (ZEEE).The
main objectives of this project are to obtain
improved multibeam bathymetric cartography
of the areas off Spanish coastlines, and to perform
a geophysical survey,well-suited with a
10-knot navigation velocity (some techniques
requires lower navigation velocity).
The geophysical survey includes gravity, geomagnetism,
and low-penetration seismic techniques
in order to infer the geological structure
of the seafloor. Other oceanographic variables
such as current, surface salinity, and temperature
profiles, can be recorded without compromising
this systematic survey effort.
The ZEEE Project has carried out its survey
activities for one month every year.Data
acquisition is achieved aboard the Spanish
R/V Hesperides. Until 1997, surveying efforts
concentrated on the Balearic Sea and Valencia
Gulf, both in the western Mediterranean Sea.
Between 1998 and 2000, the ZEEE Project
investigations were conducted offshore the
Canary Archipelago. Since 2001, the third
phase of the program has been focused on
the West Galicia Margin in the northeastern
Atlantic Ocean.
Survey results on the West Galicia Margin area
are of interest for two key reasons. First, there
is great scientific interest in the improvement
of the knowledge of this non-volcanic rifting
margin, since this margin offers good conditions
for the study of the processes that take
place in this type of geological context,because
it is sediment-starved.
Second, the obtained results also have major
socioeconomic repercussions because they
can prove significant to defining the expansion
of the Spanish shelf,beyond Spain’s Economic
Exclusive Zone distance of 200 nautical miles.
All of the gravity data acquired to date on
this area have been stored as a database, with
the aim of preparing gravity anomaly maps
on a scale 1:200,000.The database and gravity
anomaly charts from the ZEEE Project will
provide the most coherent and complete gravity
perspective available for this area.
This article describes the efforts and accomplishments
of the project to date