There has clearly been significant volcanic activity on the surface of Venus in recent geological epochs and there is a great deal of indirect evidence that this may continue at the present time. However, the current level of activity is unknown and remains controversial, with estimates for the rate of emission of volcanic gases into the atmosphere ranging from essentially quiescent to very hig...

this paper describes the application of approximate methods to invert airborne magnetic data as well as helicopter-borne frequency domain electromagnetic data in order to retrieve a joint model of magnetic susceptibility and electrical resistivity. the study area located in semnan province of iran consists of an arc-shaped porphyry andesite covered by sedimentary units which may have potential ...

Elena Nilsen, U.S. Geological Survey, Geologic Division Robert Rosenbauer, U.S. Geological Survey, Geologic Division Edward Furlong, U.S. Geological Survey, Methods Research and Development Program Mark Burkhardt, U.S. Geological Survey, Methods Research and Development Program Stephen Werner, U.S. Geological Survey, Methods Research and Development Program Lisa Greaser, U.S. Geological Survey,...

AASG/USGS Geologic Map Data Model Committee* Gary Raines, Chairman, US Geological Survey, [email protected] Boyan Brodaric, Geological Survey of Canada, [email protected] Jim Cobb, Kentucky Geological Survey, [email protected] Ralph Haugerud, US Geological Survey, [email protected] Greg Hermann, New Jersey Geological Survey, [email protected] Bruce Johnson,...

1 Acknowledgments – We acknowledge financial support from FONDECYT and FONDEF. We thank Dean Paxson,