Ben Melosh
Ben Melosh is a research geologist at the GMEG science center. He received his PhD in structural geology from McGill University in 2015. Since joining the USGS, Ben has focused on bedrock mapping and active tectonics in northern California and specializes in fault rock deformation and multiply-deformed terranes.
Professional Experience
Research Geologist, USGS, 2015 to present
Education and Certifications
Ph.D. - Structural Geology, McGill University 2015
M.S. - Active Tectonics, UC Santa Barbara 2010
B.S. - Geology, UC Santa Cruz 2005
Affiliations and Memberships*
AGU 2008-present
GSA 2008-present
CTG (Canadian tectonics group) 2011-2015
SCUMBAG (Sonoma County United Meeting of Biology and Geology) 2005-2007
Science and Products
Channel steepness and chi data for part of the northern San Francisco Bay Region including parts of the Russian River and Cache Creek watersheds, northern California
The California Coast Range are an area with a long-lived deformation history which includes modern, ongoing right lateral strike slip faulting. Large strike slip faults in the region include the San Andreas fault, the Maacama fault, the Bartlett Springs fault among many others. In areas where strike slip fault geometry changes, either in restraining or releasing bends, vertical motion...
Digital database for the geologic map along the southern Bartlett Springs fault zone and adjacent area between Cache Creek and Lake Berryessa, Northern Coast Ranges, California
This geologic map database is comprised of new geologic mapping, at a 1:24,000 scale, along the southern Bartlett Springs fault in the northern California Coast Ranges. The map covers an area of 258 square miles in Lake, Napa, Colusa, and Yolo counties, work was undertaken between 2016 and 2021, and supported by the USGS National Cooperative Geologic Map Program. This geodatabase...
Gravity, aeromagnetic, magnetic potential, and physical property data of the Bartlett Springs fault zone and surrounding areas, California
This data release contains principal facts of gravity measurements collected by the U.S. Geological Survey in 2020-2022, a compilation of existing and new density and magnetic susceptibility data, and gridded magnetic and magnetic potential data of the Bartlett Springs Fault Zone and surrounding areas, northern California. These data support modeling of gravity and magnetic anomalies to...
Geologic map and structure sections along the southern part of the Bartlett Springs Fault Zone and adjacent areas from Cache Creek to Lake Berryessa, northern Coast Ranges, California
IntroductionLocated in the Coast Ranges of northern California, the Bartlett Springs Fault Zone is the easternmost fault in the San Andreas Fault system in northern California. The fault is a right-lateral, strike-slip structure considered capable of producing an earthquake of moment magnitude 7. The purpose of this mapping is to better characterize the geology and earthquake hazards...
The geometry of fault reactivation and uplift along the central part of the Maacama fault zone, northern California Coast Ranges (USA)
Fault reactivation of bedrock structures in active fault zones influences stress state and earthquake rupture phenomena through the introduction of weak slip surfaces that impact fault zone geometry and width. Yet, geometric relationships between modern faults and older reactivated faults are difficult to quantify in rocks that have experienced multiple deformation episodes. We used new...
Authors
Benjamin L. Melosh, Robert J. McLaughlin, Henry Ohlin
Integrated geologic and geophysical modeling across the Bartlett Springs fault zone, northern California (USA): Implications for fault creep and regional structure
The rate and location at depth of fault creep are important, but difficult to characterize, parameters needed to assess seismic hazard. Here we take advantage of the magnetic properties of serpentinite, a rock type commonly associated with fault creep, to model its depth extent along the Bartlett Springs fault zone, an important part of the San Andreas fault system north of the San...
Authors
Victoria Langenheim, Robert J. McLaughlin, Benjamin L. Melosh
Fault initiation in serpentinite
Serpentinite fault rheology is fundamental to tectonic and earthquake processes, yet links between deformation textures and strength evolution during fault initiation are poorly constrained. Here I present field and petrographic microstructural observations of unsheared and sheared serpentinite that demonstrate a progression of fault development. I compliment observations with a clast...
Authors
Benjamin L. Melosh
Bedrock geology of DFDP-2B, central Alpine Fault, New Zealand
During the second phase of the Alpine Fault, Deep Fault Drilling Project (DFDP) in the Whataroa River, South Westland, New Zealand, bedrock was encountered in the DFDP-2B borehole from 238.5–893.2 m Measured Depth (MD). Continuous sampling and meso- to microscale characterisation of whole rock cuttings established that, in sequence, the borehole sampled amphibolite facies, Torlesse...
Authors
Virginia G. Toy, Rupert Southerland, John Townend, Michael J. Allen, Leeza Becroft, Austin Boles, Carolyn Boulton, Brett Carpenter, Alan K. Cooper, Simon C. Cox, Christopher Daube, Daniel R. Faulkner, Angela Halfpenny, Naoki Kato, Stephen Keys, Martina Kirilova, Yusuke Kometani, Timothy Little, Elisabetta Mariani, Benjamin L. Melosh, Catriona D. Menzies, Luiz Morales, Chance Morgan, Hiroshi Mori, Andre Niemeijer, Richard Norris, David Prior, Katrina Sauer, Anja Schleicher, Norio Shigematsu, Damon A.H. Teagle, Harold Tobin, Robert Valdez, Jack Williams, Samantha Yeo, Laura-May Baratin, Nicolas C. Barth, Adrian Benson, Caroline Boese, Bernard Celerier, Calum J. Chamberlain, Ronald Conze, Jamie Coussens, Lisa Craw, Mai-Linh Doan, Jennifer L. Eccles, Jason Grieve, Julia Grochowski, Anton Gulley, Jamie Howarth, Katrina D. Zamudio, Lucie Janku-Capova, Tamara Nicole Jeppson, Robert M. Langridge, Deirdre Mallyon, Ray Marx, Cecile Massiot, Loren Mathewson, Josephine Moore, Osamu Nishikawa, Brent Pooley, Alex Pyne, Martha K. Savage, Doug Schmitt, Sam Taylor-Offord, Phaedra Upton, Konrad C. Weaver, Thomas Wiersberg, Martin Zimmer
Science and Products
Channel steepness and chi data for part of the northern San Francisco Bay Region including parts of the Russian River and Cache Creek watersheds, northern California
The California Coast Range are an area with a long-lived deformation history which includes modern, ongoing right lateral strike slip faulting. Large strike slip faults in the region include the San Andreas fault, the Maacama fault, the Bartlett Springs fault among many others. In areas where strike slip fault geometry changes, either in restraining or releasing bends, vertical motion...
Digital database for the geologic map along the southern Bartlett Springs fault zone and adjacent area between Cache Creek and Lake Berryessa, Northern Coast Ranges, California
This geologic map database is comprised of new geologic mapping, at a 1:24,000 scale, along the southern Bartlett Springs fault in the northern California Coast Ranges. The map covers an area of 258 square miles in Lake, Napa, Colusa, and Yolo counties, work was undertaken between 2016 and 2021, and supported by the USGS National Cooperative Geologic Map Program. This geodatabase...
Gravity, aeromagnetic, magnetic potential, and physical property data of the Bartlett Springs fault zone and surrounding areas, California
This data release contains principal facts of gravity measurements collected by the U.S. Geological Survey in 2020-2022, a compilation of existing and new density and magnetic susceptibility data, and gridded magnetic and magnetic potential data of the Bartlett Springs Fault Zone and surrounding areas, northern California. These data support modeling of gravity and magnetic anomalies to...
Geologic map and structure sections along the southern part of the Bartlett Springs Fault Zone and adjacent areas from Cache Creek to Lake Berryessa, northern Coast Ranges, California
IntroductionLocated in the Coast Ranges of northern California, the Bartlett Springs Fault Zone is the easternmost fault in the San Andreas Fault system in northern California. The fault is a right-lateral, strike-slip structure considered capable of producing an earthquake of moment magnitude 7. The purpose of this mapping is to better characterize the geology and earthquake hazards...
The geometry of fault reactivation and uplift along the central part of the Maacama fault zone, northern California Coast Ranges (USA)
Fault reactivation of bedrock structures in active fault zones influences stress state and earthquake rupture phenomena through the introduction of weak slip surfaces that impact fault zone geometry and width. Yet, geometric relationships between modern faults and older reactivated faults are difficult to quantify in rocks that have experienced multiple deformation episodes. We used new...
Authors
Benjamin L. Melosh, Robert J. McLaughlin, Henry Ohlin
Integrated geologic and geophysical modeling across the Bartlett Springs fault zone, northern California (USA): Implications for fault creep and regional structure
The rate and location at depth of fault creep are important, but difficult to characterize, parameters needed to assess seismic hazard. Here we take advantage of the magnetic properties of serpentinite, a rock type commonly associated with fault creep, to model its depth extent along the Bartlett Springs fault zone, an important part of the San Andreas fault system north of the San...
Authors
Victoria Langenheim, Robert J. McLaughlin, Benjamin L. Melosh
Fault initiation in serpentinite
Serpentinite fault rheology is fundamental to tectonic and earthquake processes, yet links between deformation textures and strength evolution during fault initiation are poorly constrained. Here I present field and petrographic microstructural observations of unsheared and sheared serpentinite that demonstrate a progression of fault development. I compliment observations with a clast...
Authors
Benjamin L. Melosh
Bedrock geology of DFDP-2B, central Alpine Fault, New Zealand
During the second phase of the Alpine Fault, Deep Fault Drilling Project (DFDP) in the Whataroa River, South Westland, New Zealand, bedrock was encountered in the DFDP-2B borehole from 238.5–893.2 m Measured Depth (MD). Continuous sampling and meso- to microscale characterisation of whole rock cuttings established that, in sequence, the borehole sampled amphibolite facies, Torlesse...
Authors
Virginia G. Toy, Rupert Southerland, John Townend, Michael J. Allen, Leeza Becroft, Austin Boles, Carolyn Boulton, Brett Carpenter, Alan K. Cooper, Simon C. Cox, Christopher Daube, Daniel R. Faulkner, Angela Halfpenny, Naoki Kato, Stephen Keys, Martina Kirilova, Yusuke Kometani, Timothy Little, Elisabetta Mariani, Benjamin L. Melosh, Catriona D. Menzies, Luiz Morales, Chance Morgan, Hiroshi Mori, Andre Niemeijer, Richard Norris, David Prior, Katrina Sauer, Anja Schleicher, Norio Shigematsu, Damon A.H. Teagle, Harold Tobin, Robert Valdez, Jack Williams, Samantha Yeo, Laura-May Baratin, Nicolas C. Barth, Adrian Benson, Caroline Boese, Bernard Celerier, Calum J. Chamberlain, Ronald Conze, Jamie Coussens, Lisa Craw, Mai-Linh Doan, Jennifer L. Eccles, Jason Grieve, Julia Grochowski, Anton Gulley, Jamie Howarth, Katrina D. Zamudio, Lucie Janku-Capova, Tamara Nicole Jeppson, Robert M. Langridge, Deirdre Mallyon, Ray Marx, Cecile Massiot, Loren Mathewson, Josephine Moore, Osamu Nishikawa, Brent Pooley, Alex Pyne, Martha K. Savage, Doug Schmitt, Sam Taylor-Offord, Phaedra Upton, Konrad C. Weaver, Thomas Wiersberg, Martin Zimmer
*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government