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. During the whole period of the experiment a multi-beam sounding EM120 was used to perform bathymetric surveys. The characteristic of this sensor permitted to reach up to 11.000 m b.s.l. In table 2 we provide some of its main characteristics. During the experiment different bathymetric profiles were performed with this equipment outside of Port Foster. Some of these images already have provide an accurate vision of the region, and were used to estimate the real size of the water column locate below each shoot. Additional information of these data could be found in the Lamont-Doherty Earth Observatory at IEDA Marine Geoscience Data System (http://www.marine-geo.org/). It is possible to access the summary of downloads that were made of these data and documents at http://www.marine-geo.org/about/downloadreport/person/Ibanez_Jesus/2016A.

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 gravimeter BELL AEROSPACE-TEXTRON BGM-3 (at the present Lockheed Martin Federal Systems) is an acquisition system that can be used both in aerial and marine vehicles. The system has a sensor mounted in a gyro-stabilized platform. This system is composed of a gravimeter sensor, the stabilized platform and an acquisition system. Raw data are recorded and processed in a computer HP-486/50 using the own BGM software providing two types of data, raw and previously analyzed data. Acquired raw data are presented in the following format: $PRAWGRV, Day, Hour, Flag, Mean Value,. However, the analyzed data are transformed into: $PHESGRV, Day, Hour, Flag, Mean Value, Value GRS67, Eotvos Correction, sinv, sinv. Potential 'flag' values associated to the sensor status are: 0: normal, 2: error, 5: starting.

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.

The TOMO-DEC experiment was organized in three main legs: (1) a search for sites to deploy seismic stations and for temporary camps to accommodate the researchers (austral summer 2003-2004); (2) the field phase of data collection during the austral summer 2004-2005; and finally (3) a laboratory phase of data gathering, organization and analysis, that still ongoing as papers continue to be published. The preliminary analysis of data involved an initial phase of data gathering from instruments of different types, their organization in a joint database, their conversion to a common format and, finally, the determination of the first P-wave arrival times. Leg 1 was performed during two summer field expeditions (2002-2003 and 2003-2004). The whole island was surveyed (including glacial areas) in order to identify potential sites for seismic stations and camps. Leg 2 took place between December 2004 and March 2005 with most of the activity focused in the deployment of seismic stations (on land and OBSs), air-gun shooting, data collection and final recovery of the majority of the seismic stations. This experiment took place between January 4 and January 24, 2005. Ninety-five on-land seismic stations and 14 OBSs were deployed. They included 7 Lennartz Marslite seismic stations (covering 14 positions), four M24 instruments (covering 7 positions) and 11 seismic arrays (with 84 short period sensors, occupying a total of 101 different positions), all of them working in continuous recording mode. Active seismic sources were generated using an array of air-guns with a maximum capacity of 3520 cubic inches. Together with the seismic waveforms, a final dataset consisting of travel times for more than 70000 crustal P-wave first arrivals was collected. Bathymetric data were recorded using both EM120 and EM-1002 multi-beam sounders and a SIMRAD EA-600 single-beam sounder. Magnetic profiles were obtained using the MarineMagnetics SEASPY marine magnetometer on the base of an Overhauser sensor. Finally gravimetric data were acquired using the marine gravimeter BELL AEROSPACE-TEXTRON BGM-3. In total more than 1000 km of profiles were acquired with all types of data. The experiment at Deception Island was organized in collaboration with several research institutions. For the field work and data collection the following institutions (with number of researchers and provided instruments) participated: Instituto Andaluz De Geofisica, Spain (12, 10 land seismic arrays of malIAG type); Lamont Doherty Earth Observatory, Columbia University, USA (4, 14 OBS); INGV-Osservatorio Vesuviano, Italy (1, 7 land stations of Marslite type); INGV-Catania, Italy (1, 4 land stations of M24 type); CENAPRED, Mexico (1); Universidad De Cadiz, Spain (2); Universidad De Colima, Mexico (1); University College Dublin, Ireland (1); Universidad Complutense De Madrid, Spain (1); Universidad De La Plata, Argentina (1); University Of Washington, USA (3); USGS Volcanic Hazard Team, USA (2).