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Thermal anomaly near the Aigio fault, Gulf of Corinth, Greece, maybe due to convection below the fault
Author(s) -
Doan M. L.,
Cornet F. H.
Publication year - 2007
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2006gl028931
Subject(s) - geology , fault (geology) , geothermal gradient , seismology , borehole , rift , convection , fluid dynamics , anomaly (physics) , thermal , petrology , geophysics , mechanics , tectonics , meteorology , geotechnical engineering , physics , condensed matter physics
A thermal profile has been measured in a 1000 m deep borehole intersecting the active Aigio fault, Corinth Rift, Greece. The heat flow is 53 mW/m 2 , indicating that the rifting process has no effect in heat flow. The temperature near the fault is higher than expected from a pure conductive model. This discrepancy is not due to fluid flow above the fault as shown by the long term monitoring of downhole pressure. Neither can it be attributed to the fault slip since the Aigio fault is a minor normal fault of the rift, with no very recent earthquake. We propose that the anomaly is due to the convection within the karst that constitutes the footwall. Numerical simulations give a correct estimate for the recorded temperature increase. This is an extreme case of thermal disturbance induced near a fault by local fluid circulation. The occurrence of convection outside geothermal area is very rare.