I use seismic waveforms, typically recorded at or near the surface, to infer physical processes associated with active faulting. Recent interests include earthquake swarms (and associated fluid-faulting interactions) and tectonic tremor. To gain insight into these processes, I have worked to develop new techniques for earthquake detection, source location, and focal mechanism dete
I earned my Ph.D. from Stanford University in 2007, focused on understanding the mechanism of "non-volcanic tremor" in the Nankai subudction zone. After finishing my Ph.D., I was a Miller Postdoctoral Fellow at UC Berkeley and a Mendenhall Postdoctoral Fellow in the USGS Earthquake Science Center. From 2010-2018 I was a Research Geophysicist with the USGS Volcano Science Center (California and Yellowstone Volcano Observatories) in Menlo Park, California. I am now a member of the Geologic Hazards Science Center in Golden, Colorado.
I'm working maximize the information we can obtain from seismic records of faulting processes. This information is then combined with other available constraints (e.g. geodetic, geologic, geochemical) to understand what these seismic signals can tell us about physical (tectonic, hydrothermal, and/or magmatic) processes in the subsurface.
Other Recognitions
2015 - Editor’s Citation for Excellence in Refereeing, Geophysical Research Letters
2014 - Kavli Fellow, National Academy of Sciences
2010 - Editor’s Citation for Excellence in Refereeing, Geophysical Research Letters
Publications
Hill, D.P., E. Montgomery-Brown, D. R. Shelly, A. Flinders, and S. P. Prejean (2020), Post-1978 Tumescence at Long Valley Caldera, California: a Geophysical Perspective, Journal of Volcanology and Geothermal Research, https://doi.org/10.
Professional Experience
2018-present - Research Geophysicist, Geologic Hazards Science Center, U.S. Geological Survey, Golden, CO
2010-2018 - Research Geophysicist, Volcano Science Center, U.S. Geological Survey, Menlo Park, CA
2008-2010 - Mendenhall Postdoctoral Fellow, Earthquake Science Center, U.S. Geological Survey, Menlo Park, CA
2007-2008 - Miller Postdoctoral Fellow, Department of Earth and Planetary Science, Unversity of California, Berkeley
Education and Certifications
2007 - Ph.D., Geophysics, Stanford University, Stanford, CA
2000 - B.A. Mathematics-Physics, Whitman College, Walla Walla, WA
Honors and Awards
2012 - Macelwane Medal, presented by the American Geophysical Union for significant contributions to the geophysical sciences by an outstanding early career scientist.
2012 - Fellow, American Geophysical Union
2011 - Presidential Early Career Awards for Scientists and Engineers (PECASE) recipient, the highest honor bestowed by the United States government on science and engineering professionals in the early stages of their independent research careers.
2011 - Charles F. Richter Early Career Award, Seismological Society of America, awarded to one early career scientist annually for outstanding contributions to the Society
2008 - Inaugural recipient of the Keiiti Aki Young Scientist Award, American Geophysical Union Seismology Section, given to recognize the scientific accomplishments of a junior scientist who makes outstanding contributions to the advancement of seismology.
Science and Products
High resolution earthquake relocations and focal mechanisms with preferred fault planes for the 2020 Maacama sequence
This page contains results from analysis of 2020 Maacama earthquake sequence, including the detected and relocated earthquake catalog along with associated focal mechanisms and preferred fault planes as derived in:
Shelly, D. R., R. J. Skoumal, and J. L. Hardebeck, Fracture-mesh faulting in the swarm-like 2020 Maacama sequence revealed by high-precision earthquake detection, location, and focal m
A High-Resolution Seismic Catalog for the Initial 2019 Ridgecrest Earthquake Sequence
I use template matching and precise relative relocation techniques to develop a high-resolution earthquake catalog for the initial portion of the 2019 Ridgecrest earthquake sequence, from July 4-16, encompassing the foreshock sequence and the first 10+ days of aftershocks following the Mw 7.1 mainshock. Using 13,525 routinely cataloged events as waveform templates, I detect and precisely locate a
High resolution earthquake catalogs from the 2018 Kilauea eruption sequence
The 2018 Kilauea eruption and caldera collapse generated intense cycles of seismicity tied to repeated large seismic (Mw ~5) collapse events associated with magma withdrawal from beneath the summit. To gain insight into the underlying dynamics and aid eruption response, we applied waveform-based earthquake detection and double-difference location as the eruption unfolded. Here, we augment these ra
Filter Total Items: 19
Rapid characterization of the February 2023 Kahramanmaraş, Turkey, earthquake sequence
The 6 February 2023 Mw 7.8 Pazarcık and subsequent Mw 7.5 Elbistan earthquakes generated strong ground shaking that resulted in catastrophic human and economic loss across south‐central Türkiye and northwest Syria. The rapid characterization of the earthquakes, including their location, size, fault geometries, and slip kinematics, is critical to estimate the impact of significant seismic events.
Authors
Dara Elyse Goldberg, Tuncay Taymaz, Nadine G. Reitman, Alexandra Elise Hatem, Seda Yolsal-Çevikbilen, William D. Barnhart, Tahir Serkan Irmak, David J. Wald, Taylan Öcalan, William L. Yeck, Berkan Özkan, Jessica Ann Thompson Jobe, David R. Shelly, Eric M. Thompson, Christopher DuRoss, Paul S. Earle, Richard W. Briggs, Harley M. Benz, Ceyhun Erman, Ali Hasan Doğan, Cemali Altuntaş
Magnitude conversion and earthquake recurrence rate models for the central and eastern United States
Development of Seismic Source Characterization (SSC) models, which is an essential part of Probabilistic Seismic Hazard Analyses (PSHA), can help forecast the temporal and spatial distribution of future damaging earthquakes (𝑀w≥ 5) in seismically active regions. Because it is impossible to associate all earthquakes with known faults, seismic source models for PSHA often include sources of diffuse
Authors
Rasool Anooshehpoor, Thomas Weaver, Jon Ake, Cliff Munson, Morgan P. Moschetti, David R. Shelly, Peter M. Powers
Dense geophysical observations reveal a triggered, concurrent multi-fault rupture at the Mendocino Triple Junction
A central question of earthquake science is how far ruptures can jump from one fault to another, because cascading ruptures can increase the shaking of a seismic event. Earthquake science relies on earthquake catalogs and therefore how complex ruptures get documented and cataloged has important implications. Recent investments in geophysical instrumentation allow us to resolve increasingly complex
Authors
William L. Yeck, David R. Shelly, Dara Elyse Goldberg, Kathryn Zerbe Materna, Paul S. Earle
Using corrected and imputed polarity measurements to improve focal mechanisms in a regional earthquake catalog near the Mt. Lewis Fault Zone, California
We utilized relative polarity measurements and machine learning techniques to better resolve focal mechanisms and stress orientations considering a catalog of ∼29,000 relocated earthquakes that occurred during 1984–2021 in the southeastern San Francisco Bay Area. Earthquake focal mechanisms are commonly produced using P wave first motion polarities, which traditionally requires events to be well-r
Authors
Robert Skoumal, Jeanne L. Hardebeck, David R. Shelly
Fracture-mesh faulting in the swarm-like 2020 Maacama sequence revealed by high-precision earthquake detection, location, and focal mechanisms
In August of 2020, an earthquake sequence initiated within the Maacama fault zone in northern California, raising questions about its relationship with the larger-scale fault. To investigate the faulting geometry and its implications for physical processes driving seismicity, we applied an integrated, multi-faceted seismic analysis including waveform-correlation-based event detection, relative rel
Authors
David R. Shelly, Robert John Skoumal, Jeanne L. Hardebeck
Using machine learning techniques with incomplete polarity datasets to improve earthquake focal mechanism determination
Earthquake focal mechanisms are traditionally produced using P‐wave first‐motion polarities and commonly require well‐recorded seismicity. A recent approach that is less dependent on high signal‐to‐noise exploits similar waveforms to produce relative polarity measurements between earthquake pairs. Utilizing these relative polarity measurements, it is possible to produce composite focal mechanisms
Authors
Robert Skoumal, David R. Shelly, Jeanne L. Hardebeck
S/P amplitude ratios derived from single-component seismograms and their potential use in constraining focal mechanisms for micro-earthquake sequences
Focal mechanisms, which reflect the sense of slip in earthquakes, provide important constraints for understanding crustal tectonics and earthquake source physics, including the interactions among earthquakes during mainshock–aftershock sequences or seismic swarms. Focal mechanisms of small (magnitude ≲3.5) earthquakes are usually determined by first‐motion P‐wave polarities, sometimes supplemented
Authors
David R. Shelly, Robert John Skoumal, Jeanne L. Hardebeck
Earthquake-derived seismic velocity changes during the 2018 caldera collapse of Kīlauea volcano
The 2018 Kīlauea caldera collapse produced extraordinary sequences of seismicity and deformation, with 62 episodic collapse events which significantly altered the landscape of the summit region. Despite decades of focused scientific studies at Kīlauea, detailed information about the internal structure of the volcano is limited. Recently developed techniques in seismic interferometry can be used to
Authors
Alicia J. Hotovec-Ellis, Brian Shiro, David R. Shelly, Kyle R. Anderson, Matt Haney, Weston Thelen, Emily Montgomery-Brown, Ingrid Johanson
Identification of low-frequency earthquakes on the San Andreas fault with deep learning
Low-frequency earthquakes are a seismic manifestation of slow fault slip. Their emergent onsets, low amplitudes, and unique frequency characteristics make these events difficult to detect in continuous seismic data. Here, we train a convolutional neural network to detect low-frequency earthquakes near Parkfield, CA using the catalog of Shelly (2017), https://doi.org/10.1002/2017jb014047 as trainin
Authors
A. M. Thomas, A. Inbal, J. Searcy, David R. Shelly, R. Bürgmann
Geological constraints on the mechanisms of slow earthquakes
The recognition of slow earthquakes in geodetic and seismological data has transformed the understanding of how plate motions are accommodated at major plate boundaries. Slow earthquakes, which slip more slowly than regular earthquakes but faster than plate motion velocities, occur in a range of tectonic and metamorphic settings. They exhibit spatiotemporal associations with large seismic events t
Authors
James D. Kirkpatrick, Åke Fagereng, David R. Shelly
Post-1978 tumescence at Long Valley Caldera, California: A geophysical perspective
Long Valley Caldera has been restless since at least 1978. Prominent symptoms of this unrest include earthquake swarms and tumescence (inflation) centered on the resurgent dome. Over the years, interpretations of physical processes underlying this unrest have varied considerably. Results from a collection of geophysical studies infer the presence and/or active intrusion of magma in the crust. Geol
Authors
David P. Hill, Emily Montgomery-Brown, David R. Shelly, Ashton F. Flinders, Stephanie Prejean
Geodetic measurements of slow slip events southeast of Parkfield, CA
Tremor and low-frequency earthquakes are presumed to be indicative of surrounding slow, aseismic slip that is often below geodetic detection thresholds. This study uses data from borehole seismometers and long-baseline laser strainmeters to observe both the seismic and geodetic signatures of episodic tremor and slip on the Parkfield region of the San Andreas Fault near Cholame, CA. The observed oc
Authors
Brent G. Delbridge, Joshua D. Carmichael, Robert M. Nadeau, David R. Shelly, Roland Burgmann
Science and Products
- Data
High resolution earthquake relocations and focal mechanisms with preferred fault planes for the 2020 Maacama sequence
This page contains results from analysis of 2020 Maacama earthquake sequence, including the detected and relocated earthquake catalog along with associated focal mechanisms and preferred fault planes as derived in: Shelly, D. R., R. J. Skoumal, and J. L. Hardebeck, Fracture-mesh faulting in the swarm-like 2020 Maacama sequence revealed by high-precision earthquake detection, location, and focal mA High-Resolution Seismic Catalog for the Initial 2019 Ridgecrest Earthquake Sequence
I use template matching and precise relative relocation techniques to develop a high-resolution earthquake catalog for the initial portion of the 2019 Ridgecrest earthquake sequence, from July 4-16, encompassing the foreshock sequence and the first 10+ days of aftershocks following the Mw 7.1 mainshock. Using 13,525 routinely cataloged events as waveform templates, I detect and precisely locate aHigh resolution earthquake catalogs from the 2018 Kilauea eruption sequence
The 2018 Kilauea eruption and caldera collapse generated intense cycles of seismicity tied to repeated large seismic (Mw ~5) collapse events associated with magma withdrawal from beneath the summit. To gain insight into the underlying dynamics and aid eruption response, we applied waveform-based earthquake detection and double-difference location as the eruption unfolded. Here, we augment these ra - Multimedia
- Publications
Filter Total Items: 19
Rapid characterization of the February 2023 Kahramanmaraş, Turkey, earthquake sequence
The 6 February 2023 Mw 7.8 Pazarcık and subsequent Mw 7.5 Elbistan earthquakes generated strong ground shaking that resulted in catastrophic human and economic loss across south‐central Türkiye and northwest Syria. The rapid characterization of the earthquakes, including their location, size, fault geometries, and slip kinematics, is critical to estimate the impact of significant seismic events.AuthorsDara Elyse Goldberg, Tuncay Taymaz, Nadine G. Reitman, Alexandra Elise Hatem, Seda Yolsal-Çevikbilen, William D. Barnhart, Tahir Serkan Irmak, David J. Wald, Taylan Öcalan, William L. Yeck, Berkan Özkan, Jessica Ann Thompson Jobe, David R. Shelly, Eric M. Thompson, Christopher DuRoss, Paul S. Earle, Richard W. Briggs, Harley M. Benz, Ceyhun Erman, Ali Hasan Doğan, Cemali AltuntaşMagnitude conversion and earthquake recurrence rate models for the central and eastern United States
Development of Seismic Source Characterization (SSC) models, which is an essential part of Probabilistic Seismic Hazard Analyses (PSHA), can help forecast the temporal and spatial distribution of future damaging earthquakes (𝑀w≥ 5) in seismically active regions. Because it is impossible to associate all earthquakes with known faults, seismic source models for PSHA often include sources of diffuseAuthorsRasool Anooshehpoor, Thomas Weaver, Jon Ake, Cliff Munson, Morgan P. Moschetti, David R. Shelly, Peter M. PowersDense geophysical observations reveal a triggered, concurrent multi-fault rupture at the Mendocino Triple Junction
A central question of earthquake science is how far ruptures can jump from one fault to another, because cascading ruptures can increase the shaking of a seismic event. Earthquake science relies on earthquake catalogs and therefore how complex ruptures get documented and cataloged has important implications. Recent investments in geophysical instrumentation allow us to resolve increasingly complexAuthorsWilliam L. Yeck, David R. Shelly, Dara Elyse Goldberg, Kathryn Zerbe Materna, Paul S. EarleUsing corrected and imputed polarity measurements to improve focal mechanisms in a regional earthquake catalog near the Mt. Lewis Fault Zone, California
We utilized relative polarity measurements and machine learning techniques to better resolve focal mechanisms and stress orientations considering a catalog of ∼29,000 relocated earthquakes that occurred during 1984–2021 in the southeastern San Francisco Bay Area. Earthquake focal mechanisms are commonly produced using P wave first motion polarities, which traditionally requires events to be well-rAuthorsRobert Skoumal, Jeanne L. Hardebeck, David R. ShellyFracture-mesh faulting in the swarm-like 2020 Maacama sequence revealed by high-precision earthquake detection, location, and focal mechanisms
In August of 2020, an earthquake sequence initiated within the Maacama fault zone in northern California, raising questions about its relationship with the larger-scale fault. To investigate the faulting geometry and its implications for physical processes driving seismicity, we applied an integrated, multi-faceted seismic analysis including waveform-correlation-based event detection, relative relAuthorsDavid R. Shelly, Robert John Skoumal, Jeanne L. HardebeckUsing machine learning techniques with incomplete polarity datasets to improve earthquake focal mechanism determination
Earthquake focal mechanisms are traditionally produced using P‐wave first‐motion polarities and commonly require well‐recorded seismicity. A recent approach that is less dependent on high signal‐to‐noise exploits similar waveforms to produce relative polarity measurements between earthquake pairs. Utilizing these relative polarity measurements, it is possible to produce composite focal mechanismsAuthorsRobert Skoumal, David R. Shelly, Jeanne L. HardebeckS/P amplitude ratios derived from single-component seismograms and their potential use in constraining focal mechanisms for micro-earthquake sequences
Focal mechanisms, which reflect the sense of slip in earthquakes, provide important constraints for understanding crustal tectonics and earthquake source physics, including the interactions among earthquakes during mainshock–aftershock sequences or seismic swarms. Focal mechanisms of small (magnitude ≲3.5) earthquakes are usually determined by first‐motion P‐wave polarities, sometimes supplementedAuthorsDavid R. Shelly, Robert John Skoumal, Jeanne L. HardebeckEarthquake-derived seismic velocity changes during the 2018 caldera collapse of Kīlauea volcano
The 2018 Kīlauea caldera collapse produced extraordinary sequences of seismicity and deformation, with 62 episodic collapse events which significantly altered the landscape of the summit region. Despite decades of focused scientific studies at Kīlauea, detailed information about the internal structure of the volcano is limited. Recently developed techniques in seismic interferometry can be used toAuthorsAlicia J. Hotovec-Ellis, Brian Shiro, David R. Shelly, Kyle R. Anderson, Matt Haney, Weston Thelen, Emily Montgomery-Brown, Ingrid JohansonIdentification of low-frequency earthquakes on the San Andreas fault with deep learning
Low-frequency earthquakes are a seismic manifestation of slow fault slip. Their emergent onsets, low amplitudes, and unique frequency characteristics make these events difficult to detect in continuous seismic data. Here, we train a convolutional neural network to detect low-frequency earthquakes near Parkfield, CA using the catalog of Shelly (2017), https://doi.org/10.1002/2017jb014047 as traininAuthorsA. M. Thomas, A. Inbal, J. Searcy, David R. Shelly, R. BürgmannGeological constraints on the mechanisms of slow earthquakes
The recognition of slow earthquakes in geodetic and seismological data has transformed the understanding of how plate motions are accommodated at major plate boundaries. Slow earthquakes, which slip more slowly than regular earthquakes but faster than plate motion velocities, occur in a range of tectonic and metamorphic settings. They exhibit spatiotemporal associations with large seismic events tAuthorsJames D. Kirkpatrick, Åke Fagereng, David R. ShellyPost-1978 tumescence at Long Valley Caldera, California: A geophysical perspective
Long Valley Caldera has been restless since at least 1978. Prominent symptoms of this unrest include earthquake swarms and tumescence (inflation) centered on the resurgent dome. Over the years, interpretations of physical processes underlying this unrest have varied considerably. Results from a collection of geophysical studies infer the presence and/or active intrusion of magma in the crust. GeolAuthorsDavid P. Hill, Emily Montgomery-Brown, David R. Shelly, Ashton F. Flinders, Stephanie PrejeanGeodetic measurements of slow slip events southeast of Parkfield, CA
Tremor and low-frequency earthquakes are presumed to be indicative of surrounding slow, aseismic slip that is often below geodetic detection thresholds. This study uses data from borehole seismometers and long-baseline laser strainmeters to observe both the seismic and geodetic signatures of episodic tremor and slip on the Parkfield region of the San Andreas Fault near Cholame, CA. The observed ocAuthorsBrent G. Delbridge, Joshua D. Carmichael, Robert M. Nadeau, David R. Shelly, Roland Burgmann - News