Deep structure investigations of the geothermal field of the North Euboean Gulf, Greece, using 3-D local earthquake tomography and Curie Point Depth analysis

New findings on the deep origin of the geothermal field and volcanic centres at the North Euboean Gulf (or North Evian Gulf), Central Greece, were obtained by combining a three-dimensional traveltime inversion of microseismic data recorded by an on/offshore local seismic network with a Curie Point Depth analysis based on aeromagnetic data. A magma chamber was detected from low seismic P-wave velocity values and high Poisson ratios at depths below 8 km also coincident with a Curie surface estimated at 7-8 km depth. Furthermore, it was also observed that local geothermal anomalies are generated by hydrothermal flux facilitated by NW-SE and NE-SW oriented faults. Microseismic activity is also associated with these fault systems. (C) 2011 Elsevier B.V. All rights reserved.