Mechanisms of up-rise of the hot thermal springs of Valdieri (Argentera Massif, Maritime Alps, northwestern Italy).

In the Maritime Alps (north-western Italy), an intense seismic activity and the uprise of low-enthalpy thermal waters attest to the presence of an important tectonics active in this region (Larroque et al., 2001). The thermal springs of Terme di Valdieri, emerging in the so-called Argentera Massif (mainly composed by migmatitic gneisses), make the object of a multidisciplinary study based on hydrochemical analyses, structural surveys and numerical simulations. The studied springs up-rise along a sub-vertical NW-SE striking fault zone, showing a discontinuous en-echelon distribution and evidences of right-lateral movements (Perello et al., 2001). The integration of hydrochemical and structural data provided the framework for the on-set of numerical models describing the thermal water circulation through the fault zone. These models outline both the structural features controlling the permeability properties within fault zones both the hydrodynamic and thermal conditions constraining the thermal water circulation.