1. Department of Geological Sciences, MS 172, University of Nevada, Reno, Nevada 89557, USA
2. U.S. Geological Survey, MS 910, Menlo Park, California 94025, USA
3. Western Nevada College, 2201 West College Parkway, Carson City, Nevada 89703, USA
4. Robotic Systems Laboratory, Santa Clara University, 500 El Camino Real, Santa Clara, California 95053, USA