Geoffrey Phelps is an operational geologist specializing in the spatial analysis of geologic information in two and three dimensions.  His experience includes Quaternary geologic mapping in the Mojave desert and potential field modeling of geologic basins in southern Nevada.  Work in spatial analysis includes classification of image texture using artificial neural networks and analysis of spatial point patterns of earthquake damage and of desert vegetation.

PUBLICATIONS

Reports

Phelps, Geoffrey A., Justet, Leigh, Moring, Barry C., and Roberts,Carter W.,2005, A preliminary investigation of the structure of southern Yucca Flat, Massachusetts Mountain, and CP Basin, Nevada Test Site, Nevada, based on geophysical modeling: U.S. Geological Survey Open-File Report 2005-1367.
http://pubs.usgs.gov/of/2005/1367/

Phelps, Geoffrey A., and Roberts, Carter W., and Moring, Barry C., 2005, Preliminary gravity inversion model of basins east of Yucca Flat, Nevada Test Site, Nevada: U.S. Geological Survey Open-File Report 2005-1313.
http://pubs.usgs.gov/of/2005/1313/

Phelps, Geoffrey A., Jachens, Robert C., Moring, Barry C., and Roberts, Carter W., 2004, Modeling of the Climax Stock and Related Plutons Based on the Inversion of Magnetic data, Southwest Nevada: U.S. Geological Survey Open-File Report 2004-1345. http://pubs.usgs.gov/of/2004/1345/

Phelps, Geoffrey A., and Graham, Scott E., 2002, Preliminary model of Frenchman Flat basin, Nevada Test Site, Nevada, based on a gravity inversion model: U.S. Geological Survey Open-File Report 02-363.
http://geopubs.wr.usgs.gov/open-file/of02-363/

Phelps, Geoffrey A., Jewel, E.B., Langenheim, V.E., and Jachens, R.C., 2000, Principal Facts for Gravity Stations in the Vicinity of Coyote Spring Valley, Nevada, with Initial Gravity Modeling Results: U.S. Geological Survey Open-File Report 00-420.
http://geopubs.wr.usgs.gov/open-file/of00-420/

Phelps, Geoffrey A., Mckee, Edwin H., Sweetkind, D., and Langenheim, V.E., 2000, Preliminary model of the Pre-Tertiary basement rocks beneath Yucca Flat, Nevada Test Site, Nevada, based on analysis of gravity and magnetic data: U.S. Geological Survey Open-File Report 00-134. 
http://geopubs.wr.usgs.gov/open-file/of00-134/

Phelps, G.A., Langenheim, V.E., and Jachens, R.C., 1999, Thickness of Cenozoic deposits of yucca flat inferred from gravity data, Nevada Test Site, Nevada: U.S. Geological Survey Open-File Report 99-310, 32 p.
 http://geopubs.wr.usgs.gov/open-file/of99-310/

Phelps, Geoffrey A., and McKee, Edwin H., 1999, High-angle faults in the basement of Yucca Flat, Nevada Test Site, Nevada, based on analysis of a constrained gravity inversion surface: U.S. Geological Survey Open-File Report 99-383, 6 p.
http://geopubs.wr.usgs.gov/open-file/of99-383/

Abstracts

Phelps, G.A., Graymer, R.W., Jachens, R.C., Ponce, D.A., Simpson, R.W., and Wentworth, C.M., 2006, A prototype 3D geologic map:  the Hayward fault [abs.]: “Unlocking 3D Earth Systems - Harnessing new digital technologies to revolutionize multi-scale geologic models” GSA Penrose meeting 17-21 September 2006, Durham, UK.

Phelps, G.A., Robinson, S.E., and Miller, D.M., 2006, Investigating the spatial point patterns generated by two plant species on alluvial fan deposits of the Mojave Desert:
Association of American Geographers - Annual Meeting (March 7-11, 2006) Chicago, Illinois.

Phelps, G.A., Graymer, R.W., Jachens, R.C., Ponce, D.A., Simpson, R.W., and Wentworth, C.M., 2006, A 3-dimentional geologic map of the Hayward fault: Seismological Society of America Annual Meeting, San Francisco, CA, April 2006.

Phelps, G.A., Robinson, S.E., and Miller, D.M., 2005, Investigating plant patternson alluvial fan deposits of the Mojave Desert using high resolution imagery: Eos Trans. AGU, 86(52), Fall Meet. Suppl., Abstract B51D-0249, 2005.

Phelps, G.A., and Schmidt, K.,2005, Demonstrating that the 1989 Loma Prieta earthquake damage in southwestern Santa Clara valley is non-randomly aligned and is positively associated with mapped lineaments: Geological Society of America Cordilleran Section - 101st Annual Meeting (April 29–May 1, 2005) San Jose, California.

Phelps, Geoffrey A., 2004, Classification of Image Textures Using GRID and a Neural Network: Proceedings, ESRI International Users Conference (Aug 9-13, 2004), San Diego, California.

Phelps, G.A., and Miller, D.M., 2003, Supervised Classification of Surficial Geology Units Using Local Statistics from Digital Orthophoto Quadrangles as Input into an Artificial Neural Network: Eos Trans. AGU, 84(46), Fall Meet. Suppl., Abstract HD51-1119, 2003.

Phelps, G.A., Jachens, R.C., Wentworth, C.M., Langenheim, V.E., Hanson, R.T., and Faunt, C.C., 2003, Application Of Geowall Technology To The Analysis Of A Three Dimensional Geologic Map Of The Santa Clara (Silicon) Valley, California: Eos Trans. AGU, 84(46), Fall Meet. Suppl., Abstract ED32B-1193, 2003.

Phelps, Geoffrey, 2002, Sensitivity analysis of a gravity inversion model in Frenchman Flat Basin: EoS Trans. AGU, 83 (47), Fall Meet. Suppl., Abstract T51A-1139 p95.

Phelps, G.A., Miller, D.M., Yount, J.C., and Bedford, D.R., 1999, Modeling vulnerability and recoverability of the landscape at Valjean Valley, a pilot study area in the Mojave Desert Ecosystem, based on geologic mapping: