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Hengill geothermal volcanic complex (Iceland) characterized by integrated geophysical observations
Abstract : Structural features of volcanic and hydrothermal systems can be used to infer the location of magma chambers or productive geothermal areas. The Hengill volcanic triple-junction complex has a well-developed geothermal system, which is being exploited to extract hot fluids that are used for electrical power and heat production. In the framework of the I-GET project, a 4- month temporary seismological network including seven highdynamic broadband instruments was deployed and 1D transient electromagnetic soundings (TEM) and 3D magnetotelluric (MT) surveys were performed to improve understanding of the relationships between structural features, seismic activity and fluid production at the Hengill geothermal system. The MT and TEM data set is analyzed elsewhere. The analysis of the seismological data set allowed the detection and classification of more than 600 earthquakes, among which long-period (LP) earthquakes were observed for the first time in this area. This work focuses first on a joint inversion for the 3D velocity structure and determination of the locations of the hypocentres from about 250 local volcano-tectonic earthquakes with clear Pand S- wave arrival times. The results confirm those from earlier tomography studies in this area. Integrating the seismic velocity and resistivity models in a semi-quantitative approach by crossplotting the resistivity model with the velocity ratio VP/VS delineates a structural body with a high seismic velocity ratio and low resistivity that is interpreted as the main heat source of the geothermal system.
Littérature citée [104 références]
https://hal-brgm.archives-ouvertes.fr/hal-00562003
Contributeur : Philippe Jousset Connectez-vous pour contacter le contributeur
Soumis le : mercredi 2 février 2011 - 15:31:28
Dernière modification le : lundi 11 octobre 2021 - 13:02:03
Archivage à long terme le : : mardi 3 mai 2011 - 03:20:30
Contributeur : Philippe Jousset Connectez-vous pour contacter le contributeur
Soumis le : mercredi 2 février 2011 - 15:31:28
Dernière modification le : lundi 11 octobre 2021 - 13:02:03
Archivage à long terme le : : mardi 3 mai 2011 - 03:20:30
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