Affiliation: | Institute of Geophysics, Georgian Ac. Sci. 1, Alexidze str. 380093, Tbilisi, Georgia and Geosciences Rennes, Universite de Rennes 1, 35042, Rennes, France,; Ecole Normale Supérieure, Laboratoire de Géologie, Dep. TAO, 24, rue Lhomond, Paris, France. E-mail: |