Hydrothermal fluid flow triggered by an earthquake in Iceland

Microearthquake hypocenters were analyzed in the Krysuvik 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-tobottom fluid migration in the upper crust. We observe from our surveys a complex bottomto-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.

Automated summary

Based on seismic surveys conducted in the Krysuvik geothermal area in SW-Iceland, it was observed that there is a complex migration of seismicity in the area. This suggests a connection between the migration of fluid and the upper-crust fracture system.