Affiliation: | Instituto de Geociências, Universidade de Brası´lia, 70910-900;Brası´lia, DF Brazil. E-mail: Departamento de Engenharia Elétrica, Universidade de Brası´lia, 70910-900;Brası´lia, DF Brazil Institut de Physique du Globe de Paris, 14;Route Nationale 3, 27ème km, 97418 La Plaine des Cafres, Isle de la Reunion, France Microsoft Research, Microsoft Corporation, One Microsoft Way, Redmond, WA 98052‐6399,;USA |