[1
]U.S. Geological Survey; 345 Middlefield Rd., MS989,>; Menlo Park; California; 94025;
USA
[2
]U.S. Geological Survey; 4210 University Dr.,; Anchorage; Alaska; 99508-4626; USA
[3
]Geosoft Inc.; 1600 SW Western Blvd., Ste. 250,; Corvallis; Oregon; 97333-4122; USA