Hydrothermal fluid flow triggered by an earthquake in Iceland

Laurent Geoffroy (1) , Catherine Dorbath (2) , Kristján Ágústsson , Sigrídur Kristjánsdóttir , Ólafur G. Flóvenz , Cécile Doubre (2) , Ólafur Gudmundsson , Thibaut Barreyre , Sarah Bazin (1) , Aurore Franco (1)

1 IUEM - Institut Universitaire Européen de la Mer
2 EOST - Ecole et Observatoire des Sciences de la Terre

Microearthquake hypocenters were analyzed in the Krýsuvík geothermal area in SW-Iceland with data taken from two consecutive passive seismic surveys, 2005 and 2009. Five years prior to the 2005 survey, this area was struck by an earthquake initiating a major top-to-bottom fluid migration in the upper crust. We observe from our surveys a complex bottom-to-top migration of seismicity with time following this fluid penetration, suggesting the migration of a pore pressure front controlled by the upper-crust fracture system. We interpret these data as the time and space development of high-temperature hydrothermal cells from a deep upper crustal fluid reservoir in the supercritical field. These results provide an insight into the coupling mechanisms between active tectonics and fluid flow in upper-crustal extensional systems with high thermal flux.

Domains: Sciences of the Universe [physics]

Laurent Geoffroy, Catherine Dorbath, Kristján Ágústsson, Sigrídur Kristjánsdóttir, Ólafur G. Flóvenz, et al.. Hydrothermal fluid flow triggered by an earthquake in Iceland. Communications Earth & Environment, 2022, 3, ⟨10.1038/s43247-022-00382-0⟩. ⟨insu-03684621⟩