1. National Geophysical Research Institute; Council of Scientific and Industrial Research; Hyderabad 500606 India
2. National Remote Sensing Centre; Indian Space Research Organization; Hyderabad 500036 India
3. Department of Geological Sciences; Brown University; Providence RI USA
4. Space Applications Centre; Indian Space Research Organization; Ahmedabad 380015 India
5. School of Earth and Space Exploration; Arizona State University; Tempe Arizona USA
6. Lunar and Planetary Institute; Universities Space Research Organization; Houston Texas USA
7. Physical Research Laboratory; Ahmedabad 380009 India