Geoffrey Phelps, MSc
Phelps works in the GMEG Science Center. He received a BA in geology from UC Berkeley and an MSc from the University of London, Birkbeck in geographic information science. He specializes in geologic mapping, gravity and magnetics, and spatial analysis. Presently his research is focused on using data science tools in 2D and 3D geologic mapping, and gravity and magnetic forward and inverse modeling.
Science and Products
Uncrewed aerial system aeromagnetic test survey at the Boulder Magnetic Observatory Uncrewed aerial system aeromagnetic test survey at the Boulder Magnetic Observatory
This data release contains two related datasets acquired for the uncrewed aerial system aeromagnetic test survey at the Boulder Magnetic Observatory. The first contains the raw magnetic data for the set of four test flights, and the second contains the compensated magnetic data for the same four flights. Details of the data are recorded in the metadata files associated with each dataset.
Geophysical datasets for the FORGE Fallon site Geophysical datasets for the FORGE Fallon site
The datasets include geophysical and rock property measurements and models accompanying the FORGE Fallon Phase II study
Filter Total Items: 29
A time-lapse gravity survey of the Coso geothermal field, China Lake Naval Air Weapons Station, California A time-lapse gravity survey of the Coso geothermal field, China Lake Naval Air Weapons Station, California
We have conducted a gravity survey of the Coso geothermal field to continue the time-lapse gravity study of the area initiated in 1991. In this report, we outline a method of processing the gravity data that minimizes the random errors and instrument bias introduced into the data by the Scintrex CG-5 relative gravimeters that were used. After processing, the standard deviation of the...
Authors
Geoffrey Phelps, Collin Cronkite-Ratcliff, Kelly Blake
Analysis of the age and paleomagnetic orientation of the Broadwell Mesa Basalt, Bristol Mountains, CA Analysis of the age and paleomagnetic orientation of the Broadwell Mesa Basalt, Bristol Mountains, CA
To add to the regional paleomagnetic data documenting block rotation in eastern California, we determined the age and paleomagnetic rotation of the Broadwell Mesa basalt, a basalt in the Bristol Mountains, CA as part of an effort to constrain the timing and rotation of blocks adjacent to the fault. The east-striking sinistral Broadwell Mesa fault cuts and separates the basalt into two...
Authors
Geoffrey Phelps, John Hillhouse, Robert J. Fleck, David M. Miller, David C. Buesch, Andrew J. Cyr, Kevin M. Schmidt
Active tectonics of the northern Mojave Desert: The 2017 Desert Symposium field trip road log Active tectonics of the northern Mojave Desert: The 2017 Desert Symposium field trip road log
The 2017 Desert Symposium field trip will highlight recent work by the U.S. Geological Survey geologists and geophysicists, who have been mapping young sediment and geomorphology associated with active tectonic features in the least well-known part of the eastern California Shear Zone (ECSZ). This area, stretching from Barstow eastward in a giant arc to end near the Granite Mountains on...
Authors
David M. Miller, R.E. Reynolds, Geoffrey Phelps, Jeffrey S. Honke, Andrew J. Cyr, David C. Buesch, Kevin M. Schmidt, G. Losson
Geologic setting of the proposed West Flank Forge Site, California: Suitability for EGS research and development Geologic setting of the proposed West Flank Forge Site, California: Suitability for EGS research and development
The proposed West Flank FORGE site is within the China Lake Naval Air Weapons Station (NAWS), China Lake, CA. The West Flank is west of the Coso geothermal field, an area of China Lake NAWS dominated by the Quaternary Coso volcanic field largely comprised of rhyolite domes and their volcaniclastic and epiclastic horizons. The largest dome flow complex, Sugarloaf Mountain, marks the...
Authors
Andrew Sabin, Kelly Blake, Mike Lazaro, Douglas Blankenship, Mack Kennedy, Jess McCullough, S.B. DeOreo, Stephen H. Hickman, Jonathan M.G. Glen, J. Ole Kaven, Colin F. Williams, Geoffrey Phelps, James E. Faulds, Nicholas H. Hinz, Wendy M. Calvin, Drew Siler, Ann Robertson-Tait
Geologic setting of the West Flank, a FORGE site adjacent to the Coso geothermal field Geologic setting of the West Flank, a FORGE site adjacent to the Coso geothermal field
The West Flank FORGE (Frontier Observatory for Research in Geothermal Energy) site is located immediately west and outside of the Coso geothermal field, eastern California. Coso is a fluid-dominated, high temperature geothermal system that has been producing power continuously since 1987. The reservoir is composed of highly faulted, fractured and hydrothermally altered Cretaceous and...
Authors
Andrew Sabin, Kelly Blake, Mike Lazaro, Dave Meade, Douglas Blankenship, Mack Kennedy, Jess McCulloch, Steve DeOreo, Stephen H. Hickman, Jonathan M.G. Glen, J. Ole Kaven, Martin Schoenball, Colin F. Williams, Geoffrey Phelps, James Faulds, Nick Hinz, Wendy Calvin, Drew Siler, Ann Robertson-Tait
Forward modeling of gravity data using geostatistically generated subsurface density variations Forward modeling of gravity data using geostatistically generated subsurface density variations
Using geostatistical models of density variations in the subsurface, constrained by geologic data, forward models of gravity anomalies can be generated by discretizing the subsurface and calculating the cumulative effect of each cell (pixel). The results of such stochastically generated forward gravity anomalies can be compared with the observed gravity anomalies to find density models...
Authors
Geoffrey Phelps
Science and Products
Uncrewed aerial system aeromagnetic test survey at the Boulder Magnetic Observatory Uncrewed aerial system aeromagnetic test survey at the Boulder Magnetic Observatory
This data release contains two related datasets acquired for the uncrewed aerial system aeromagnetic test survey at the Boulder Magnetic Observatory. The first contains the raw magnetic data for the set of four test flights, and the second contains the compensated magnetic data for the same four flights. Details of the data are recorded in the metadata files associated with each dataset.
Geophysical datasets for the FORGE Fallon site Geophysical datasets for the FORGE Fallon site
The datasets include geophysical and rock property measurements and models accompanying the FORGE Fallon Phase II study
Filter Total Items: 29
A time-lapse gravity survey of the Coso geothermal field, China Lake Naval Air Weapons Station, California A time-lapse gravity survey of the Coso geothermal field, China Lake Naval Air Weapons Station, California
We have conducted a gravity survey of the Coso geothermal field to continue the time-lapse gravity study of the area initiated in 1991. In this report, we outline a method of processing the gravity data that minimizes the random errors and instrument bias introduced into the data by the Scintrex CG-5 relative gravimeters that were used. After processing, the standard deviation of the...
Authors
Geoffrey Phelps, Collin Cronkite-Ratcliff, Kelly Blake
Analysis of the age and paleomagnetic orientation of the Broadwell Mesa Basalt, Bristol Mountains, CA Analysis of the age and paleomagnetic orientation of the Broadwell Mesa Basalt, Bristol Mountains, CA
To add to the regional paleomagnetic data documenting block rotation in eastern California, we determined the age and paleomagnetic rotation of the Broadwell Mesa basalt, a basalt in the Bristol Mountains, CA as part of an effort to constrain the timing and rotation of blocks adjacent to the fault. The east-striking sinistral Broadwell Mesa fault cuts and separates the basalt into two...
Authors
Geoffrey Phelps, John Hillhouse, Robert J. Fleck, David M. Miller, David C. Buesch, Andrew J. Cyr, Kevin M. Schmidt
Active tectonics of the northern Mojave Desert: The 2017 Desert Symposium field trip road log Active tectonics of the northern Mojave Desert: The 2017 Desert Symposium field trip road log
The 2017 Desert Symposium field trip will highlight recent work by the U.S. Geological Survey geologists and geophysicists, who have been mapping young sediment and geomorphology associated with active tectonic features in the least well-known part of the eastern California Shear Zone (ECSZ). This area, stretching from Barstow eastward in a giant arc to end near the Granite Mountains on...
Authors
David M. Miller, R.E. Reynolds, Geoffrey Phelps, Jeffrey S. Honke, Andrew J. Cyr, David C. Buesch, Kevin M. Schmidt, G. Losson
Geologic setting of the proposed West Flank Forge Site, California: Suitability for EGS research and development Geologic setting of the proposed West Flank Forge Site, California: Suitability for EGS research and development
The proposed West Flank FORGE site is within the China Lake Naval Air Weapons Station (NAWS), China Lake, CA. The West Flank is west of the Coso geothermal field, an area of China Lake NAWS dominated by the Quaternary Coso volcanic field largely comprised of rhyolite domes and their volcaniclastic and epiclastic horizons. The largest dome flow complex, Sugarloaf Mountain, marks the...
Authors
Andrew Sabin, Kelly Blake, Mike Lazaro, Douglas Blankenship, Mack Kennedy, Jess McCullough, S.B. DeOreo, Stephen H. Hickman, Jonathan M.G. Glen, J. Ole Kaven, Colin F. Williams, Geoffrey Phelps, James E. Faulds, Nicholas H. Hinz, Wendy M. Calvin, Drew Siler, Ann Robertson-Tait
Geologic setting of the West Flank, a FORGE site adjacent to the Coso geothermal field Geologic setting of the West Flank, a FORGE site adjacent to the Coso geothermal field
The West Flank FORGE (Frontier Observatory for Research in Geothermal Energy) site is located immediately west and outside of the Coso geothermal field, eastern California. Coso is a fluid-dominated, high temperature geothermal system that has been producing power continuously since 1987. The reservoir is composed of highly faulted, fractured and hydrothermally altered Cretaceous and...
Authors
Andrew Sabin, Kelly Blake, Mike Lazaro, Dave Meade, Douglas Blankenship, Mack Kennedy, Jess McCulloch, Steve DeOreo, Stephen H. Hickman, Jonathan M.G. Glen, J. Ole Kaven, Martin Schoenball, Colin F. Williams, Geoffrey Phelps, James Faulds, Nick Hinz, Wendy Calvin, Drew Siler, Ann Robertson-Tait
Forward modeling of gravity data using geostatistically generated subsurface density variations Forward modeling of gravity data using geostatistically generated subsurface density variations
Using geostatistical models of density variations in the subsurface, constrained by geologic data, forward models of gravity anomalies can be generated by discretizing the subsurface and calculating the cumulative effect of each cell (pixel). The results of such stochastically generated forward gravity anomalies can be compared with the observed gravity anomalies to find density models...
Authors
Geoffrey Phelps