Christopher W Johnson main menu

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White Rock Canyon : Los Alamos, NM

Welcome

I am a Feynman Distinguished Postdoctoral Fellow at Los Alamos National Laboratory in the Earth and Environmental Sciences Division: Geophysics (EES-17).

Research
- Earthquake triggering
- Dynamics of seismicity
- Microseismicity detection
- Hydrogeodesy
- Surface loading & elastic deformation

These topics are explored using advanced signal processing techniques, machine learning, and high performance computing to mine information from continuous seismic waveforms

Metrics
Google Scholar h-index 11

Strawberry Creek : Berkeley, CA

About

After working as a diesel technician, I obtained a Bachelors Degree in Geophysics at Georgia Tech. There I particiapted in a research project investigating geologic and geodetic slip rates discrepancies in Eastern CA. Before graduating I was a NSF Graduate Research Fellowship Program recipient and attended UC Berkeley to study seismology, geodesy, and active tectonics.

In 2017 I completed my PhD with Roland Burgmann at the Berkeley Seismological Laboratory after completing projects on triggered seismic activity from transient crustal stress changes, dynamics of siesmicity from geothermal fluid injection, surface loading, terrestrial water storage, and interseismic deformation.

In 2017 I was awarded a NSF Postdoctoral Fellowship and transitioned to Scripps Institution of Oceanography at UC San Diego to study earthquake detection techniques and seismic noise discrimination using machine learning. The fellowship allowed me to focus on new research directions in seismology and geodesy. I collaborated with Frank Vernon (UCSD/IGPP) and Yehuda Ben-Zion (USC) on projects focusing on seismic noise modulation from atmospheric coupling and applying machine learning signal classification using dense seismic array data and regional seismic network data.

My current position is a Feynman Distinguished Postdoctoral Fellow at Los Alamos National Laboratory. I am applying machine learning algorithms to investigate the properties of seismic noise for earthquake detection applications. My long-term goal is an academic or research appointment to continue investigating geophysical problems and explore the dynamics of planet Earth

Joshua trees : Clayton Valley, NV

Research

Earthquake Triggering and Dynamics of seismicity

Spatiotemporal variations in seismic activity, clustering, and transient stress triggering provide insight to the evolving state of stress in the crust. I investigate crustal stress variations atmospheric coupling, surface water loading, and earthquake interaction. Each process produces a repeatable large-scale source used to probe the crustal response to contrain fault mechanical models.
The deployment of dense nodal arrays are an excellent tool for exploring shallow crustal properties and developing new microseismicity detection techniques. I apply high performance computing and machine learning to large databases of seismic waveforms to characterize transient signals and identify weak ground motions.

Surface Loading and Hydrogeodesy

Atmosphere, hydrosphere, thermal variations, and tides all deform the crust elastically and can modulate the stresses on active faults. Seasonality in these processes provide a repeatable loading source that modualtes the state of stress in the crust. Using geodetic network data I characterize the elastic surface loading using GPS and GRACE data to inform deformation models that describe the evolving state of stress in the crust. As time series of continuous data extend to decadal scales these applicatoins can be applied to interannual deformation cycle related to climate variations.

Redwoods : Crescent City, CA

CV

Full CV (PDF)

Education and Appointments

Richard P. Feynman Postdoctoral Fellow, 2020 - 2023
Los Alamos National Laboratory
EES-17 Geophysics
Los Alamos, New Mexico

NSF Postdoctoral Fellow 2017 - 2020
Scripps Institution of Oceanography
Institute of Geophysics and Planetary Physics
University of California, San Diego

NSF Graduate Research Fellowship Program 2012-2017
Ph.D. 2017 Berkeley Seismological Laboratory
University of California, Berkeley, CA
Dissertation: Stress modulation of earthquakes: A study of long and short period stress perturbations and the crustal response

Undergraduate
B.Sc. 2012, Highest Honors, GPA: 4.0
School of Earth and Atmospheric Sciences
Georgia Institute of Technology
Undergraduate Thesis: Measuring Present-Day Strain Rates along the Fish Lake Valley Fault System, Pacific-North America Plate Boundary

Awards and Honors

Feynman Distinguished Postdoctoral Fellowship, 2020-2023
National Science Foundation Postdoctoral Research Fellowship, 2017-2019
Louderback Award, Earth and Planetary Science, UC Berkeley, 2017
National Science Foundation Graduate Research Fellowship Program, 2012-2017
Rutt Bridges Research Initiative Award, Undergraduate initiated research salary, 2011
Presidential Undergraduate Research Award, Undergraduate initiated research salary, 2011
Anadarko/SEG Tuition Scholarship, 2011 – 2012
Georgia Hope Scholar, full tuition scholarship, 2008 – 2011

Invited Talks

GAGE/SAGE 2020 Science Workshop, Breckenridge, CO, Aug 2020 CANCELED COVID-19
Japan Geoscience Union Meeting 2020, Chiba, Japan, May 2020 CANCELED COVID-19
University of Southern California, Los Angeles, CA, November 2019
Los Alamos National Lab, Los Alamos, NM, July 2019
California Institute of Technology, Pasadena, CA, July 2019
University of Grenoble Alpes, Grenoble, France, June 2019
IGPP, UC SanDiego, San Diego, CA, April 2019
IRIS Workshop 2018, Albuquerque, New Mexico, June 2018
Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokohama, Japan, May 2018
Japan Geoscience Union Meeting 2018, Chiba, Japan, May 2018
IGPP, UC SanDiego, San Diego, CA, Feb 2018
Department of Geological Sciences, University of Florida, Gainesville, FL, Feb 2018
American Geophysical Union Fall Meeting 2017, New Orleans, LA, Dec 2017
Institute of Earth Sciences, Academia Sinica, Taipei, Taiwan. Keynote Speaker, Sept 2017
Dept. of Earth Sciences, National Taiwan Normal Univ., Taipei, Taiwan, Sept 2017
Lawrence Berkeley National Lab. Berkeley, CA, July 2017
Computation in Geophysics Workshop. Denver, CO, June 2017
EarthScope National Meeting. Anchorage, AK, May 2017
Department of Geological Sciences, University of Texas at Austin. Austin, TX, April 2017

Collaborators

Yehuda Ben-Zion, Uni. of Southern California, Los Angeles
Adrian Borsa, Uni. of California, San Diego
Florent Brenguier, Uni. of Grenoble Alpes, Grenoble, France
Roland Bürgmann (PhD Advisor), Uni. of California, Berkeley
Estelle Chaussard, Uni. of Oregon, Eugene, Oregon
Kate Chen, National Taiwan Normal Uni.
Pierre Dutilleul, McGill Uni., Montreal, Canada
Yuning Fu, Bowling Green State Uni., Ohio
Peter Gerstoft, Uni. of California, San Diego
Paul Johnson, Los Alamos Nat. Lab., New Mexico
Debi Kilb, Uni. of California, San Diego
Frank Vernon, Uni. of California, San Diego

Skills

Computing: Python, Matlab, Fortran, C, BASH
Data processing: ObsPy, Tensorflow, SAC, ISCE
Document / Presentation: Adobe, Office platform, Overleaf
Language: English (native), Spanish (can communicate)
Additional: ASE Master Level Technician Medium/Heavy Trucks (2003-2008)

Alabama Hills : Owens Valley, CA

Publications

Google Scholar h-index 11

In review

Johnson, C.W., Lau, N., Borsa, A. (in ESS review), An assessment of GPS velocity uncertainty

Snover, D., Johnson, C.W., Bianco, M.J., Gerstoft, P. (in SRL review) Deep clustering to identify sources of urban seismic noise in Long Beach, CA

Dutilleul, P.R.L., C.W. Johnson, R. Bürgmann (in EEST review) Marked spatio-temporal point patterns, periodicity analysis and earthquakes: an analytical extension including hypocenter depth.

Dutilleul, P.R.L., C.W. Johnson, R. Bürgmann (in GRL review) Periodicity Analysis of Earthquake Occurrence and Hypocenter Depth near Parkfield, California, 1994-2002 versus 2006-2014

2020

[27] Johnson, C.W., Ben-Zion, Y., Meng, H., Vernon, F.L. (2020), Identifying different classes of seismic noise signals using unsupervised learning Geophysical Research Letters, 47. doi:10.1029/2020GL088353 Link

[26] Cheng, Y., Ben-Zion, Y., Brenguier, F., Johnson, C. W., Li, Z., Share, P., Mordret, A., Boué, P., Vernon F.L. (2020) Automated method for developing catalog of small earthquakes using data of dense seismic array and nearby stations.doi:10.1785/0220200134 Link

[25] Johnson, C.W., D. Kilb, A. Baltay, and F. Veron (2020), Peak ground velocity spatial variability revealed by dense seismic array in southern California Journal of Geophysical Research: Solid Earth, 125. doi:10.1029/2019JB019157 Link

[24] Xue, L., C.W. Johnson, Y. Fu and R. Bürgmann (2020) Seasonal seismicity in the Western Branch of the East African Rift System, Geophys. Res. Lett.,47, doi:10.1029/2019GL085882 Link

[23] Johnson, C. W., Y. Fu, and R. Bürgmann (2020), Hydrospheric modulation of stress and seismicity on shallow faults in southern Alaska. Earth and Planetary Science Letters, doi:10.1016/j.epsl.2019.115904 Link

2019

[22] Brenguier, F., Boué, P., Ben-Zion, Y., Vernon, F., Johnson, C. W., Mordret, A., et al. (2019) Train traffic as a powerful noise source for monitoring active faults with seismic interferometry. Geophysical Research Letters. doi:10.1029/2019gl083438 Link

[21] Meng, H., Y. Ben-Zion, C.W. Johnson (2019) Detection of random noise and anatomy of continuous seismic waveforms in dense array data near Anza California. Geophysical Journal International. doi:10.1093/gji/ggz349 Link

[20] Johnson, C.W., H. Meng, F.L. Vernon, and Y. Ben-Zion (2019) Characteristics of ground motion generated by interaction of wind gusts with trees, structures and other obstacles above the surface. Journal of Geophysical Research: Solid Earth, 124. doi:10.1029/2018jb017151 Link

[19] Qin, L., F.L. Vernon, C.W. Johnson, and Y. Ben-Zion (2019) Spectral characteristics of daily to seasonal ground motions using coherences at the Piñon Flats Observatory.Bulletin of the Seismological Society of America doi: https://doi.org/10.1785/0120190070 Link

[18] Johnson, C.W., F.L. Vernon, N. Nakata, and Y. Ben-Zion (2019) Atmospheric Processes Modulating Noise in Fairfield Nodal 5 Hz Geophones. Seismological Research Letters, https://doi.org/10.1785/0220180383 Link

2018

[17] Xu, W., Wu, S., Materna, K., Nadeau, R., Floyd, M., Funning, G., Chaussard, E., Johnson, C.W., Murray, J.R., Ding, X., Bürgmann, R. (2018) Interseismic ground deformation and fault slip rates in the greater San Francisco Bay Area from two decades of space geodetic data. Journal of Geophysical Research: Solid Earth, 123. https://doi.org/10.1029/2018JB016004 Link

[16] Chen, K. H., Tai, H.‐J., Ide, S., Byrne, T., Johnson, C. W. (2018). Tidal modulation and tectonic implications of tremors in Taiwan. Journal of Geophysical Research: Solid Earth, 123. https://doi.org/10.1029/2018JB015663 Link

[15] Xue, L., R. Bürgmann, D.R. Shelly, C.W. Johnson, T. Taira (2018) Kinematics of the 2015 San Ramon, California earthquake swarm: Implications for fault zone structure and driving mechanisms. Earth and Planetary Science Letters, 489. doi.org/10.1016/j.epsl.2018.02.018 Link

[14] M.T. Ramírez-Herrera, K. Gaidzik, S. Forman, V. Kostoglodov, R. Bürgmann, C.W. Johnson (2018) Relating the long-term and short-term vertical deformation across a transect of the forearc in the central Mexican subduction zone. Geosphere; 14 (2): 419–439. doi: https://doi.org/10.1130/GES01446.1 Link

2017

[13] Johnson, C. W., Y. Fu, and R. Bürgmann (2017), Stress models of the annual hydrospheric, atmospheric, thermal, and tidal loading cycles on California faults: Perturbation of background stress and changes in seismicity, Journal of Geophysical Research: Solid Earth, 122. https://doi.org/10.1002/2017JB014778 Link

[12] Han, L., Z. Peng, C.W. Johnson, F.F. Pollitz, L. Li, B. Wang, J.Wu, Q. Li (2017) Shallow microearthquakes near Chongqing, China triggered by the Rayleigh waves of the 2015 M7.8 Gorkha, Nepal earthquake, EPSL, doi:10.1016/j.epsl.2017.09.024. Link

[11] Johnson, C. W., Y. N. Fu, and R. Burgmann (2017), Seasonal water storage, stress modulation, and California seismicity, Science, 356(6343), 1161-1164, doi:10.1126/science.aak9547. Link

[10] Delbridge, B.G, S. Kita, N. Uchida, C. W. Johnson, T. Matsuzawa, and R. Bürgmann (2017), Temporal variation of intermediate depth earthquakes around the time of to the M 9.0 Tohoku-Oki earthquake, Geophysical Research Letters, doi:10.1002/2017GL072876. Link

2016

[9] Johnson,C.W., E.J.Totten, and R. Bürgmann (2016), Depth migration of seasonally induced seismicity at The Geysers geothermal field, Geophys. Res. Lett., 43,6196–6204, doi:10.1002/2016GL069546. Link

[8] Chaussard, E., C. W. Johnson, H. Fattahi, and R. Bürgmann (2016), Potential and limits of InSAR to characterize interseismic deformation independently of GPS data: application to the southern San Andreas Fault system, Geochemistry, Geophysics, Geosystems. Link

2015

[7] Johnson, C. W., and R. Bürgmann (2015), Delayed dynamic triggering: Local seismicity leading up to three remote M≥6 aftershocks of the 11 April 2012 M8.6 Indian Ocean earthquake, J. Geophys. Res. Solid Earth, 120, doi:10.1002/2015JB012243. Link

[6] Dutilleul, P., C. W. Johnson, R. Bürgmann, Y. Wan, and Z.-K. Shen (2015), Multi-frequential periodogram analysis of earthquake occurrence: An alternative approach to the Schuster spectrum, with two examples in central California, J. Geophys. Res. Solid Earth, 120, doi:10.1002/2015JB012467. Link

[5] Chaussard, E., R. Bürgmann, H. Fattahi, C. W. Johnson, R. Nadeau, T. Taira, and I. Johanson (2015), Interseismic coupling and refined earthquake potential on the Hayward-Calaveras fault zone, J. Geophys. Res. Solid Earth, 120, doi:10.1002/2015JB012230. Link

[4] Chaussard, E, R Bürgmann, H Fattahi, RM Nadeau, T Taira, CW Johnson, and I Johanson (2015), Potential for larger earthquakes in the East San Francisco Bay Area due to the direct connection between the Hayward and Calaveras Faults. Geophys. Res. Lett., 42, 2734–2741. doi: 10.1002/2015GL063575. Link

[3] Johnson, C. W., R. Burgmann, and F. F. Pollitz (2015), Rare dynamic triggering of remote M≥5.5 earthquakes from global catalog analysis, Journal of Geophysical Research: Solid Earth, 120, doi:10.1002/2014JB011788. Link

2013

[2] Lifton, Z.M., A. V. Newman, K. L. Frankel, C.W. Johnson, and T. H. Dixon (2013), Insights into distributed plate rates across the Walker Lane from GPS geodesy, Geophys. Res. Lett., 40, doi:10.1002/grl.50804. Link

2012

[1] Foy, T. A., K. L. Frankel, Z. M. Lifton, C. W. Johnson, M. W. Caffee (2012), Distributed extensional deformation in a zone of right-lateral shear: Implications for geodetic versus geologic rates of deformation in the eastern California shear zone-Walker Lane, Tectonics, 31, TC4008, doi:10.1029/2011TC002930. Link

Eureka Dunes : Death Valley, CA

Media Coverage

EOS Editors' Highlights, Masumi Yamada, Super Dense Array Measurement Magnifies Seismic Wavefields. Published on 5 August 2020. Link

Kornei, K. (2019), Wind-triggered ground shaking masks microseismicity, Eos, 100, https://doi.org/10.1029/2019EO130989. Published on 20 August 2019. Link

Seasonal water changes may trigger earthquakes, UC Berkeley researchers say, Jana Katsuyama, KTVU, 06/16/2017

Something You Probably Didn’t Expect From the Huge Sierra Snowpack: Earthquakes, Craig Miller, NPR station KQED, 06/15/2017 Link

San Andreas Fault Earthquakes Are Triggered by Winter Rain and Snow, Scientists Discover, Hannah Osborne, Newsweek, 06/15/2017 Link

Shifting water weight can trigger small earthquakes in California, Warren Cornwall, Sciencemag, 06/15/2017 Link

Rain and snow help stress out earthquake faults, A little bit, Mary Beth Griggs, Popular Science, 06/15/2017 Link

How Rain and Snow Could Play a Role in Triggering Earthquakes, John Perritano, How Stuff Works, 06/22/2017 Link

Snow and rain tug on earthquake faults in California, Maria Temming, Science News, 07/03/2017 Link

UNAVCO March 2016 Annual Workshop Ingite Talk

Outreach

Instructor for Sally Ride Science, UC San Diego Extension

Library NExT Instructor for pre-college classes hosted at San Diego public libraries 2018-2019

Sally Ride Science Junior Academy One-week summer program instructor Summer 2018. Being an instructor for SRS is a rewarding experince that provides the opportunity to interact with middle and high students. We explore topics on geology in California, discuss geophysics and the educational training necessary to pursue careers in science and engineering, and perform experiments to demonstate the basics of faulting and earthquakes.

Birch Aquarium 2018 ShakeOut!

Interact with guests to explain the ShakeOut program and hazards associeted with strong ground shaking

EPS Department Coordinator for Bay Area Science in Schools outreach program organized by Community Resources for Science (crscience.org) from 2015-2017.

Travel to local middle schools, with a focus on underrepresented communities, and give 1-2 hour lessons with a lab component on earthquake faulting, liquefaction, and safety.

Provide professional development seminars for elementary and middle school teachers covering general Earth science and earthquake safety.

Lead activities for the Berkeley Seismological Laboratory outreach program for visitors.

Bristlecone Pines : White Mountains, CA

Field Work

Select images from the field

2019 geophone campaign Tule Canyon and Palomar Mnt

2018 field campaign deploying 400 geophones at Piñon Flat Observatory

2018 San Jacinto Fault Zone seismometer maintence

2017 Dry Wash on San Jacinto Fault Zone. Removal of 5 year temporary seismometer deployment

2013 San Jacinto Fault Zone geochronology survey

2010-2012 GPS campaign around the White Mountains and Fish Lake Valley Fault

2010 Clayton Valley geochronology survey

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