Study of the Structure of Deception volcanic complex by means of marine geophysical techniques

In English:

During the GEODEC-MAR sub-project, gravimetric observations were performed at
the Argentine Station main reference point, as well as at a new geodetic
reference located situated in the nearby of Spanish Antarctic Station (SAS)
"Gabriel de Castilla". 60 gravimetric measurements and 58 magnetic measurements
were taken at Deception Island. Additionally, measurements were done at
Livingston Island, such as in the SAS "Juan Carlos I" surroundings, at Byers
Peninsula, and at Low Island too. Due to similar concerns on land seismic
activities portable seismic stations were installed at Deception Island (DI),
SAS "Juan Carlos I", Byers Peninsula and Low Island. Data at the seismic
lines midway were acquired by the use of 9 marine seismometer anchorage (Ocean
Bottom Seismometer, OBS). Among them, 8 were anchored out of Deception island
and one inside its internal bay (Port Foster). Two OBS were lost.

Concerning the marine survey:
-Marine survey out of DI:
Gravimetric, magnetic and bathymetric data were obtained. The study area was
near 230 Km wide and 250 Km length. Additional lines were done were seismic was
acquired (by means of BOLT airguns) as well as gravimetric, magnetic and
bathymetric data.
-Marine survey inside of DI:
Seismic information was obtained by the use of airguns, as well as bathymetric
and potential field information. A shallow marine survey was performed towing a
marine magnetometer (GEOMAG SMM II) at Port Foster by the use of a pneumatic
boat.

The complete marine survey covered slightly more than 3000 nautical miles, from
almost 100 marine track lines. 63 seismic record sections were performed based
on portable seismic stations and 19 seismic record sections from OBS.

En Español:

Durante los tres años de duracion del subproyecto GEODEC-MAR, se realizaron
observaciones gravimetricas en el punto fundamental existente en la Base
Argentina, y en el nuevo vertice construido en las inmediaciones de la Base
Antartica Española "Gabriel de Castilla". Se realizaron un total de 60 nuevas
medidas gravimetricas y 58 medidas geomagneticas. Ademas de estas, realizadas
en la Isla Decepcion, se midieron asimismo en la Isla Livingston, tanto en las
proximidades de la Base Antartica Española "Juan Carlos I", como en las
inmediaciones del campamento que se instalo en la Península de Byers. Se
instalaron estaciones sísmicas portatiles en la Isla decepcion, BAE "Juan
Carlos I", Península de Byers e Isla Low.

Se adquirieron datos en los puntos intermedios de las líneas sísmicas
realizando un total de 9 fondeos de sismometros de fondo marino (Ocean Botton
Sismometer, OBS), ocho de ellos fondeados en puntos exteriores a la Isla
Decepcion y uno en sus aguas exteriores. De los nueve OOBS fondeados se
recuperaron siete.

Las líneas barridas por el BIO Hesperides fueron:

Lineas exteriores a Isla Decepcion con adquisicion de datos gravimetricos,
geomagneticos y batimetricos. Se cubrieron una zona de dimensiones aproximadas
de 230 km de ancho y 250 km de largo.

Líneas exteriores a isla decepcion con adquisicion de datos sísmicos. Se
desplegaron cañones de aire BOLT. Y durente su barrido se procedion a la
adquisicion de datos gravimetricos, geomagneticos y batimetricos.

Líneas interiores a isla Decepcion. Se realizaron con cañones de aire y
adicionalmente se adquirieron datos gravimetricos y batimetricos. Se realizo un
barrido marino en las aguas someras de Puerto Foster, mediante el empleo de
embarcacion neumatica remolcando un magnetometro marino GOMAG SMIL.

El computo total de millas navegadas barriendo líneas es de mas de 3000 millas
nauticas, repartidas en un total de casi 100 líneas.

Se realizaron 63 ensamblajes de perfiles sísmicos a partir de diferentes
estaciones sísmicas terrestres y 19 ensamblajes a partir de OBS.