TOMODEC. High resolution seismic tomography of Deception Island (Antarctica), and modelling of seismo-volcanic sources. MAGNETIC DATA

In January 2005 a multi-parametric international experiment was conducted that encompassed both Deception Island and its surrounding waters. This experiment used as main platforms the Spanish Oceanographic vessel 'Hesperides', the Spanish Scientific Antarctic base 'Gabriel de Castilla' at Deception Island and four temporary camps deployed on the volcanic island. This experiment allowed us to record active seismic signals on a large network of seismic stations that were deployed both on land and on the seafloor. In addition other geophysical data were acquired, such as: bathymetric high precision multi-beam data, and gravimetric and magnetic profiles. The magnetometer SeaSPY is an acquisition system from the Company Marine Magnetics with a very sensitive and omnidirectional Overhauser sensor. This sensor allows measurement of the total magnetic field and was stable in time during the survey period. This system has a high-precision clock (1 ppm) and it can be synchronized with the onboard GPS clock. This equipment is thermally stabilized permitting it to operate in all type of sea waters, including Antarctic waters, and due to its design there are no heading errors. In table 4 we summarize its technical characteristics. The magnetometer was used during the first phase of shooting outside of Post Foster. However, its 200 m long tow cable precluded its use inside the Deception Island inner bay.