Katherine (Kate) Scharer
Dr. Scharer holds a Ph.D. from the University of Oregon and a B.S. in Geological Sciences from the University of Washington.
Prior to coming to the USGS, she was a professor at Appalachian State University in North Carolina. Dr. Scharer studies the timing and size of pre-historic earthquakes along the San Andreas Fault and other active faults in southern California, Alaska, and the Dominican Republic. She also investigates the deformation produced by tectonic motion through a combination of field mapping, lidar analysis, and Quaternary geochronologic methods.
Science and Products
Data release for spatial and temporal analysis of geologically derived fault slip rates, Cucamonga Fault, California, USA Data release for spatial and temporal analysis of geologically derived fault slip rates, Cucamonga Fault, California, USA
This report summarizes the age-dating results from two alluvial fan surfaces (map units Qyf2 and Qyf3) that are broken by strands of the Cucamonga Fault, in southern California, at Day Canyon and Etiwanda Canyon. Within this report are detailed the methodology used to collect samples of rock and sediment, determine concentrations of cosmogenic beryllium-10 in purified quartz isolated...
Earthquake geology inputs for the U.S. National Seismic Hazard Model (NSHM) 2023 (western US) (ver. 2.0, February 2022) Earthquake geology inputs for the U.S. National Seismic Hazard Model (NSHM) 2023 (western US) (ver. 2.0, February 2022)
This Data Release contains preliminary versions of two related databases: 1) A fault sections database ('NSHM23_FSD_v2'), which depicts the geometry of faults capable of hosting independent earthquakes, and 2) An earthquake geology site information database ('NSHM23_EQGeoDB_v2'), which contains fault slip-rate constraints at points. These databases were prepared in anticipation of...
STEPS: Slip Time Earthquake Path Simulations applied to the San Andreas and Toe Jam Hill faults to redefine geologic slip rate uncertainty (Matlab code) STEPS: Slip Time Earthquake Path Simulations applied to the San Andreas and Toe Jam Hill faults to redefine geologic slip rate uncertainty (Matlab code)
Geologic slip rates are a time-averaged measurement of fault displacement calculated over 100s- to 1,000,000-year time scales and are a primary input for probabilistic seismic hazard analyses (PSHA), which forecast expected ground shaking in future earthquakes. Despite their utility for seismic hazard calculations, longer-term geologic slip rates represent a time-averaged measure of the...
Earthquake geology inputs for the U.S. National Seismic Hazard Model (NSHM) 2023, version 1.0 Earthquake geology inputs for the U.S. National Seismic Hazard Model (NSHM) 2023, version 1.0
This Data Release contains preliminary versions of two related databases: 1) A fault sections database ("NSHM2023_FaultSections_v1"), which depicts the geometry of faults capable of hosting independent earthquakes, and 2) An earthquake geology site information database ("NSHM2023_EQGeoDB_v1"), which contains fault slip-rate constraints at points. These databases were prepared in...
Surface Displacement Observations of the 2019 Ridgecrest, California Earthquake Sequence Surface Displacement Observations of the 2019 Ridgecrest, California Earthquake Sequence
Surface rupture associated with the 2019 Ridgecrest, California earthquake sequence includes the dominantly left-lateral and northeast-striking M6.4 rupture and dominantly right-lateral and northwest-striking M7.1 rupture. This data release includes surface-displacement observations of these ruptures made by teams of federal, state, academic, and private sector geologists between July...
Filter Total Items: 49
Spatial and temporal analysis of geologic slip rates, Cucamonga Fault, California, USA: Implications for along-strike applications and multi-fault rupture Spatial and temporal analysis of geologic slip rates, Cucamonga Fault, California, USA: Implications for along-strike applications and multi-fault rupture
To constrain fault processes and hazard, fault slip rates may be extrapolated over different fault lengths or time intervals. Here, we investigate slip rates for the Cucamonga Fault (CF). The CF is located at the junction of the Transverse Range fault system with the San Andreas and San Jacinto Faults, and it is hypothesized to connect with these faults, promoting the propagation of...
Authors
Devin McPhillips, Katherine M. Scharer
Survey of fragile geologic features and their quasi-static earthquake ground-motion constraints, southern Oregon Survey of fragile geologic features and their quasi-static earthquake ground-motion constraints, southern Oregon
Fragile geologic features (FGFs), which are extant on the landscape but vulnerable to earthquake ground shaking, may provide geological constraints on the intensity of prior shaking. These empirical constraints are particularly important in regions such as the Pacific Northwest that have not experienced a megathrust earthquake in written history. Here, we describe our field survey of...
Authors
Devin McPhillips, Katherine M. Scharer
Observation-constrained multicycle dynamic models of the southern San Andreas and the northern San Jacinto Faults: Addressing complexity in paleoearthquake extent and recurrence with realistic 2D fault geometry Observation-constrained multicycle dynamic models of the southern San Andreas and the northern San Jacinto Faults: Addressing complexity in paleoearthquake extent and recurrence with realistic 2D fault geometry
Understanding mechanical conditions that lead to complexity in earthquakes is important to seismic hazard analysis. In this study, we simulate physics-based multicycle dynamic models of the San Andreas fault (Carrizo through San Bernardino sections) and the San Jacinto fault (Claremont and Clark strands). We focus on a complex fault geometry based on the Southern California Earthquake...
Authors
Dunyu Liu, Benchuan Duan, Katherine M. Scharer, Doug Yule
STEPS: Slip time earthquake path simulations applied to the San Andreas and Toe Jam Hill Faults to redefine geologic slip rate uncertainty STEPS: Slip time earthquake path simulations applied to the San Andreas and Toe Jam Hill Faults to redefine geologic slip rate uncertainty
Geologic slip rates are a time-averaged measurement of fault displacement calculated over hundreds to million-year time scales and are a primary input for probabilistic seismic hazard analyses, which forecast expected ground shaking in future earthquakes. Despite their utility for seismic hazard calculations, longer-term geologic slip rates represent a time-averaged measure of the tempo...
Authors
Alexandra Elise Hatem, Ryan D. Gold, Richard W. Briggs, Katherine M. Scharer, Edward H. Field
SSA task force on diversity, equity, and inclusion: Toward a changing, inclusive future in earthquake science SSA task force on diversity, equity, and inclusion: Toward a changing, inclusive future in earthquake science
In the United States, a wide variety of studies show that the geoscience community does not reflect the broader societal makeup (e.g., Velasco and Jaurrieta de Velasco, 2010; Dutt, 2020; Howley, 2020). In fact, only about 10% of all Science, Technology, Engineering, and Mathematics (STEM) Ph.D. degrees are awarded to people of color, although they represent more than a third of the...
Authors
Aaron A. Velasco, Kasey Aderhold, Richard Alfaro-Diaz, Wesley Brown, Mike Brudzinski, Margaret Fraiser, Monique M. Holt, Jim Mori, Gabriela Noriega, Katherine M. Scharer, Denise Templeton, Fabia Terra, Sherilyn Williams-Stroud
Late Holocene slip rate of the Mojave section of the San Andreas Fault near Palmdale, California Late Holocene slip rate of the Mojave section of the San Andreas Fault near Palmdale, California
The geologic slip rate on the Mojave section of the San Andreas fault is poorly constrained, despite its importance for understanding earthquake hazard, apparent discrepancies between geologic and geodetic slip rates along this fault section, and long‐term fault interactions in southern California. Here, we use surficial geologic mapping, excavations, and radiocarbon and luminescence...
Authors
Elaine Young, Eric Cowgill, Katherine M. Scharer, Emery Anderson-Merritt, Amanda Keen-Zebert, Ray J. Weldon
Science and Products
Data release for spatial and temporal analysis of geologically derived fault slip rates, Cucamonga Fault, California, USA Data release for spatial and temporal analysis of geologically derived fault slip rates, Cucamonga Fault, California, USA
This report summarizes the age-dating results from two alluvial fan surfaces (map units Qyf2 and Qyf3) that are broken by strands of the Cucamonga Fault, in southern California, at Day Canyon and Etiwanda Canyon. Within this report are detailed the methodology used to collect samples of rock and sediment, determine concentrations of cosmogenic beryllium-10 in purified quartz isolated...
Earthquake geology inputs for the U.S. National Seismic Hazard Model (NSHM) 2023 (western US) (ver. 2.0, February 2022) Earthquake geology inputs for the U.S. National Seismic Hazard Model (NSHM) 2023 (western US) (ver. 2.0, February 2022)
This Data Release contains preliminary versions of two related databases: 1) A fault sections database ('NSHM23_FSD_v2'), which depicts the geometry of faults capable of hosting independent earthquakes, and 2) An earthquake geology site information database ('NSHM23_EQGeoDB_v2'), which contains fault slip-rate constraints at points. These databases were prepared in anticipation of...
STEPS: Slip Time Earthquake Path Simulations applied to the San Andreas and Toe Jam Hill faults to redefine geologic slip rate uncertainty (Matlab code) STEPS: Slip Time Earthquake Path Simulations applied to the San Andreas and Toe Jam Hill faults to redefine geologic slip rate uncertainty (Matlab code)
Geologic slip rates are a time-averaged measurement of fault displacement calculated over 100s- to 1,000,000-year time scales and are a primary input for probabilistic seismic hazard analyses (PSHA), which forecast expected ground shaking in future earthquakes. Despite their utility for seismic hazard calculations, longer-term geologic slip rates represent a time-averaged measure of the...
Earthquake geology inputs for the U.S. National Seismic Hazard Model (NSHM) 2023, version 1.0 Earthquake geology inputs for the U.S. National Seismic Hazard Model (NSHM) 2023, version 1.0
This Data Release contains preliminary versions of two related databases: 1) A fault sections database ("NSHM2023_FaultSections_v1"), which depicts the geometry of faults capable of hosting independent earthquakes, and 2) An earthquake geology site information database ("NSHM2023_EQGeoDB_v1"), which contains fault slip-rate constraints at points. These databases were prepared in...
Surface Displacement Observations of the 2019 Ridgecrest, California Earthquake Sequence Surface Displacement Observations of the 2019 Ridgecrest, California Earthquake Sequence
Surface rupture associated with the 2019 Ridgecrest, California earthquake sequence includes the dominantly left-lateral and northeast-striking M6.4 rupture and dominantly right-lateral and northwest-striking M7.1 rupture. This data release includes surface-displacement observations of these ruptures made by teams of federal, state, academic, and private sector geologists between July...
Filter Total Items: 49
Spatial and temporal analysis of geologic slip rates, Cucamonga Fault, California, USA: Implications for along-strike applications and multi-fault rupture Spatial and temporal analysis of geologic slip rates, Cucamonga Fault, California, USA: Implications for along-strike applications and multi-fault rupture
To constrain fault processes and hazard, fault slip rates may be extrapolated over different fault lengths or time intervals. Here, we investigate slip rates for the Cucamonga Fault (CF). The CF is located at the junction of the Transverse Range fault system with the San Andreas and San Jacinto Faults, and it is hypothesized to connect with these faults, promoting the propagation of...
Authors
Devin McPhillips, Katherine M. Scharer
Survey of fragile geologic features and their quasi-static earthquake ground-motion constraints, southern Oregon Survey of fragile geologic features and their quasi-static earthquake ground-motion constraints, southern Oregon
Fragile geologic features (FGFs), which are extant on the landscape but vulnerable to earthquake ground shaking, may provide geological constraints on the intensity of prior shaking. These empirical constraints are particularly important in regions such as the Pacific Northwest that have not experienced a megathrust earthquake in written history. Here, we describe our field survey of...
Authors
Devin McPhillips, Katherine M. Scharer
Observation-constrained multicycle dynamic models of the southern San Andreas and the northern San Jacinto Faults: Addressing complexity in paleoearthquake extent and recurrence with realistic 2D fault geometry Observation-constrained multicycle dynamic models of the southern San Andreas and the northern San Jacinto Faults: Addressing complexity in paleoearthquake extent and recurrence with realistic 2D fault geometry
Understanding mechanical conditions that lead to complexity in earthquakes is important to seismic hazard analysis. In this study, we simulate physics-based multicycle dynamic models of the San Andreas fault (Carrizo through San Bernardino sections) and the San Jacinto fault (Claremont and Clark strands). We focus on a complex fault geometry based on the Southern California Earthquake...
Authors
Dunyu Liu, Benchuan Duan, Katherine M. Scharer, Doug Yule
STEPS: Slip time earthquake path simulations applied to the San Andreas and Toe Jam Hill Faults to redefine geologic slip rate uncertainty STEPS: Slip time earthquake path simulations applied to the San Andreas and Toe Jam Hill Faults to redefine geologic slip rate uncertainty
Geologic slip rates are a time-averaged measurement of fault displacement calculated over hundreds to million-year time scales and are a primary input for probabilistic seismic hazard analyses, which forecast expected ground shaking in future earthquakes. Despite their utility for seismic hazard calculations, longer-term geologic slip rates represent a time-averaged measure of the tempo...
Authors
Alexandra Elise Hatem, Ryan D. Gold, Richard W. Briggs, Katherine M. Scharer, Edward H. Field
SSA task force on diversity, equity, and inclusion: Toward a changing, inclusive future in earthquake science SSA task force on diversity, equity, and inclusion: Toward a changing, inclusive future in earthquake science
In the United States, a wide variety of studies show that the geoscience community does not reflect the broader societal makeup (e.g., Velasco and Jaurrieta de Velasco, 2010; Dutt, 2020; Howley, 2020). In fact, only about 10% of all Science, Technology, Engineering, and Mathematics (STEM) Ph.D. degrees are awarded to people of color, although they represent more than a third of the...
Authors
Aaron A. Velasco, Kasey Aderhold, Richard Alfaro-Diaz, Wesley Brown, Mike Brudzinski, Margaret Fraiser, Monique M. Holt, Jim Mori, Gabriela Noriega, Katherine M. Scharer, Denise Templeton, Fabia Terra, Sherilyn Williams-Stroud
Late Holocene slip rate of the Mojave section of the San Andreas Fault near Palmdale, California Late Holocene slip rate of the Mojave section of the San Andreas Fault near Palmdale, California
The geologic slip rate on the Mojave section of the San Andreas fault is poorly constrained, despite its importance for understanding earthquake hazard, apparent discrepancies between geologic and geodetic slip rates along this fault section, and long‐term fault interactions in southern California. Here, we use surficial geologic mapping, excavations, and radiocarbon and luminescence...
Authors
Elaine Young, Eric Cowgill, Katherine M. Scharer, Emery Anderson-Merritt, Amanda Keen-Zebert, Ray J. Weldon