HR: 14:35h
AN: NS33A-03    [Abstracts]
TI: An airborne hydrogeophysical study of San Christobal, Galapagos Islands
AU: * Auken, E
EM: esben.auken@geo.au.dk
AF: Department of Earth Sciences, University of Aarhus, Department of Earth Sciences, University of Aarhus, Denmark
AU: d'Ozouville, N
EM: noemi.dozouville@ccr.jussieu.fr
AF: Université Pierre et Marie Curie, UMR7619-Sisysphe, case 123, 4 place Jussieu, 75252 Paris Cedex 05, France,
AU: Violette, S
EM: Sophie.Violette@ccr.jussieu.fr
AF: Université Pierre et Marie Curie, UMR7619-Sisysphe, case 123, 4 place Jussieu, 75252 Paris Cedex 05, France,
AU: de Marsily, G
EM: gdemarsily@aol.com
AF: Université Pierre et Marie Curie, UMR7619-Sisysphe, case 123, 4 place Jussieu, 75252 Paris Cedex 05, France,
AU: Deffontaines, B
EM: benoit.deffontaines@univ-mlv.fr
AF: Universtié de Marne-la-Vallée, Laboratoire de Géomatériaux et Géologie de l'Ingénieur, 5 Bd. Descartes, Champs-sur-Marne, F-77454 Marne-la-Vallée, Cedex 2,
AU: Viezzoli, A
EM: andrea.viezzoli@geo.au.d
AF: Department of Earth Sciences, University of Aarhus, Department of Earth Sciences, University of Aarhus, Denmark
AU: Sorensen, K
EM: kurt.sorensen@geo.au.dk
AF: Department of Earth Sciences, University of Aarhus, Department of Earth Sciences, University of Aarhus, Denmark
AB: Airborne electromagnetic methods are practical tools for large scale hydrogeophysical mappings. In this presentation we show initial results from a study on the volcanic island of San Christobal, one of the islands in the Galapagos archipelago. The survey is an essential part of a project aiming on characterizing the entire hydrological system on this island and the island of Santa Cruz. The island has a serious growing lack of quality drinking water. A total number of about 800 km of time domain electromagnetic data were measured using the helicopter borne system, SkyTEM. The SkyTEM system is specially developed for high resolution surveys, the first time gate is measured at 15 micros and the maximum magnetic moment is approx. 105 kAm2. Data does not require levelling. The data were processed using state of the art filtering techniques and inverted using a newly developed 3D sharp boundary inversion algorithm with locally 1D derivatives. We discuss pros and cons of the applied methodology and present results from the survey. The results clearly reveal the saltwater boundary and outlines distinct structural differences between the western and central zone in relation with their different hydrological characteristics.
UR: http:www.hgg.au.dk
DE: 0684 Transient and time domain
DE: 1880 Water management (6334)
SC: Near-Surface Geophysics [NS]
MN: 2007 Joint Assembly