Bill Walter

Staff Scientist
Atmospheric, Earth, and Energy Division
Phone: +19254238777


  • Ph.D., Geophysics, University of Nevada, Reno, 1991
  • M.Sc., Physics, University of California at San Diego, 1986
  • B.A., Physics, Middlebury College, 1984

Research Interests

Geophysics and seismology, seismic source physics, earthquake scaling, explosion models, seismic waves from the collapse of underground cavities, nuclear explosion monitoring, treaty verification and related policy issues, earth structure.

Selected Honors and Awards

  • Global Security Directorate External Review Committee, best presentation award, 2017
  • Physics and Life Science Directorate Award for outstanding postdoc mentor, 2009
  • Earth and Environmental Sciences Directorate Award for effective postdoc program, 1999
  • Phi Kappa Phi Honor Society, University of Nevada, Reno, 1991
  • Institute of Global Conflict and Cooperation/Sloan Foundation Fellowship, 1985–1986
  • Graduated Cum Laude with High Honors in Physics, Middlebury College, 1984

Selected Service Activities

  • President of the Seismological Society of America - April 2020–April 2021
  • Seismological Society of America Board of Directors - elected member 2016–2021
  • National Academy of Sciences Committee on Seismology and Geodynamics member 2016–2021
  • National Academy of Sciences CTBT Study member of the Seismology Subcommittee, published report “The Comprehensive Nuclear Test Ban Treaty: Technical Issues for the United States“ in 2012.
  • Member of IRIS Global Seismic Network Standing Committee, 2015–2018
  • Member IRIS Data Management System Standing Committee, 2008–2010
  • Member IRIS Standing Committee on PASSCAL, 2003-2005
  • Associate Editor, Bulletin of the Seismological Society of America, 1995–2003

Selected Publications

W. R. Walter is the author or co-author of more than 75 publications in peer-reviewed journals

Walter, W. R., "Finding, Organizing and Preserving Legacy Nuclear Test Monitoring Data - Examples from the Livermore Nevada Network", Seismological Research Letters, https://doi:10.1785/0220190286.  (published online 12 Feb 2020)

Pyle, M.L., and W.R. Walter, Investigating the Effectiveness of P/S Amplitude Ratios for Local Distance Event Discrimination,  Bulletin of the Seismological Society of America, vol. 109, no. 3 pp. 1071-1081, (June 2019) doi:/10.1785/0120180256

Walter, W. R., D. A. Dodge, G. Ichinose, S. C. Myers, M. E. Pasyanos and S. R. Ford, (2018). Body-wave methods of distinguishing between explosions, collapses and earthquakes – application to recent events in North Korea, Seis. Res. Lett. doi: 10.1785/0220180128

Ichinose, G. A., S. C. Myers, S. R. Ford, M. E. Pasyanos, and W. R. Walter, (2017). Relative Surface-wave Amplitude and Phase Anomalies from the Democratic People's Republic Korea Announced Nuclear Tests, Geophysical Research Letters, 44, 8857-8864, doi:10.1002/2017GL074577. 

Walter, W. R., Yoo, S-H., K. Mayeda and R. Gok, (2017). Earthquake Stress Via Event Ratio Levels: Application to the 2011 and 2016 Oklahoma Seismic Sequences, Geophys. Res. Lett., 44, doi:10.1002/2016GL072348.

Pyle, M. L, W. R. Walter, and M. E. Pasyanos, (2017). High-resolution 2D Lg and Pg Attenuation Models in the Basin and Range Region with Implications for Frequency-Dependent Q, Bull. Seismol. Soc. Am., 107, 2846-2858, doi: 10.1785/0120170172.

Gok, R., A. Kaviani, E.M. Matzel, M.E. Pasyanos, K. Mayeda, I. El-Hussain, A. Al-Amri, A. Al-Enezi, G. Yetirmishli, T. Godoladze, D. Kalafat, E.A. Sandvol and W.R. Walter (2016). Moment magnitudes of local/regional events from 1-D coda calibrations in the broader Middle East region, Bull. Seism. Soc. Amer., 106, 1926-1938, doi: 10.1785/0120160045.

Pasyanos. M.E., R. Gok, and W.R. Walter (2016). 2-D variations in coda amplitudes in the Middle East, Bull. Seism. Soc. Amer., 106 (5), 1915-1925, doi:10.1785/0120150336.

Chiang, A., D. S. Dreger, S. R. Ford, W. R. Walter, and S.-H. Yoo, (2016). Moment Tensor Analysis of Very Shallow Sources, Bull. Seis. Soc. Am., 106, 2436-2449, DOI:10.1785/0120150233

Dodge, D. A. and W. R. Walter (2015). Initial Global Seismic Cross-Correlation Results: Implications for Empirical Signal Detectors, Bull. Seism. Soc. Am. 105, 240-256, doi: 10.1785/0120140166

Addair, T. G., D.A. Dodge, W.R. Walter, and S.D. Ruppert, (2014). Large-scale seismic signal analysis with Hadoop, Computers & Geosciences, Volume 66, May 2014, Pages 145-154, ISSN 0098-3004,

Ford, S. and W. R. Walter, (2013). An Explosion Model Comparison with Insights from the Source Physics Experiments, Bull. Seism. Soc. Am., 103, 2937-2945, doi:10.1785/0120130035.

Snelson, C., R. Abbott, S. Broome, R. Mellors, H. Patton, A. Sussman, M. Townsend and W. Walter, (2013), "Source Physics Experiment to Validate a New Paradigm for Nuclear Test Monitoring", EOS trans. AGU vol. 94, No. 27, July 2, 2013

Ford, S. R., D.S. Dreger, and W. R. Walter, (2009). Identifying isotropic events using a regional moment tensor inversion, J. Geophys. Res., 114 B01306, doi:10.1029/2008JB005743.

Pasyanos, M.E., and W. R. Walter, (2009). Improvements to regional explosion identification using attenuation models of the lithosphere, Geophys. Res. Lett., 36, L14304, doi:10.1029/2009GL038505

Mayeda, K., L. Malagnini, and W. R. Walter, (2007). A new spectral ratio method using narrow band coda envelopes: Evidence for non-self-similarity in the Hector Mine sequence, Geophys. Res. Lett, 34, L11303, doi:10.1029/2007GL030041.

Walter, W. R., K. Mayeda, R. Gok and A. Hofstetter, (2006). The scaling of seismic energy with moment: simple models compared with observations, in “Earthquakes: Radiated Energy and the Physics of Faulting” American Geophysical Union Monograph 170, doi:10.1029/170GM05, 25-41.

Vincent, P., S. Larsen, D. Galloway, R. J. Laczniak, W. R. Walter, W. Foxall, and J. J. Zucca, (2003). New signatures of underground nuclear tests revealed by satellite radar interferometry, Geophys. Res. Lett., Vol. 30, No. 22, doi:10.1029/2003GL018179.

Bowers, D. and W. R. Walter, Discriminating between large mine collapses and explosions using teleseismic P-waves, Pure Appl. Geophys., 159, 803-830, 2002

Taylor, S. R., A. A. Velasco, H. E.  Hartse, W. S. Phillips, W. R. Walter and A. J. Rodgers, (2002). Amplitude corrections for regional seismic discriminants, Pure Appl. Geophys., 159, 623-650.

Rodgers, A. W. R. Walter, Y. Zhang R. Mellors and A. M. S. Al-Amri, (1999). Lithospheric structure within the Arabian peninsula from complete regional waveform modeling and surface wave group velocities, J. Geophys. Int., 138, 871-878.

Myers, S. C., W. R. Walter, K. Mayeda and L. Glenn, (1999). Observations in support of Rg  scattering as a source for explosion S waves: regional and local recordings of the 1997 Kazakhstan depth of burial experiment, Bull. Seism. Soc. Am. 89, 544-549.

McNamara, D. E., W. R. Walter, T. J. Owens, and C. J. Ammon, (1997). Upper mantle velocity struture beneath the Tibetan Plateau from Pn travel time tomography, J. Geophys. Res. 102, 493-505.

McNamara, D. E., T. J. Owens, and W. R. Walter, Propagation characteristics of Lg across the Tibetan Plateau, Bull. Seism. Soc. Am.86, 457-469, 1996

Mayeda, K. M. and W. R. Walter, (1996). Moment, energy, stress drop and source spectra of Western U.S. earthquakes from regional coda envelopes, J. Geophys. Res101, 11,195-11,208.

Walter, W. R., K. M. Mayeda and H. J. Patton, (1995). Phase and spectral ratio discrimination between NTS earthquakes and explosions, part I: empirical observations, Bull. Seism. Soc. Am. 85, 1050-106.

Pechmann, J. C., W. R. Walter, S. J. Nava, and W. J. Arabasz, (1995). The February 3, 1995 ML 5.1 seismic event in the trona mining district of southwestern Wyoming, Seism. Res. Lett., 66, 25-34.

Walter, W. R. and J. N. Brune, (1993). The spectra of seismic radiation from a tensile crack, J. of Geophys. Res., 98, 4449-445.

Walter, W. R., (1993). Source parameters of the June 29, 1992 Little Skull Mountain earthquake from complete regional waveforms at a single station, Geophys. Res. Lett., 20, 403-406.

Walter, W. R., and H. J. Patton, (1990). Tectonic release from the Soviet joint verification experiment, Geophys. Res. Lett., 17, 1517-1520.