Department of Geological and Environmental Sciences, Stanford University, 450 Serra Mall; Braun Hall, Building 320, Stanford, CA 94305-2115 United States
US Geological Survey, 345 Middlefield Rd., Menlo Park, CA 94025-3591 United States
Department of Geological and Environmental Sciences, Stanford University, 450 Serra Mall; Braun Hall, Building 320, Stanford, CA 94305-2115 United States