Ned Field
Ned (Edward) Field is a Research Geophysicist with the Earthquake Hazards Program.
Ned Field coordinates and leads the development of earthquake forecast models for the USGS Earthquake Hazards Program. These forecasts, coupled with ground-motion models, form the basis of modern seismic hazard and risk analyses. Their development is multidisciplinary and collaborative (a "systems science" problem) in that information from a broad range of disciplines (e.g., seismology, geodesy, geology, paleoseismology, and earthquake physics) must reconciled.
Recent accomplishments and ongoing challenges involve representation of multi-fault ruptures and spatiotemporal clustering (e.g., aftershocks), improved uncertainty estimates, applying more physics-based approaches, and the need to add "valuation" to our verification and validation protocols (i.e., a greater focus on usefulness). Ned is also involved in developing and deploying end-to-end seismic hazard and risk computational platforms. The resultant models influence a variety of risk mitigation activities, including construction requirements (building codes) and earthquake insurance rates.
Science and Products
A-priori rupture models for Northern California Type-A faults
Development of final a-fault rupture models for WGCEP/ NSHMP Earthquake Rate Model 2
Forecasting California's earthquakes— What can we expect in the next 30 years?
Documentation for the 2008 update of the United States National Seismic Hazard Maps
Grid computing in the SCEC community modeling environment
Hazard calculations for the WGCEP-2002 earthquake forecast using OpenSHA and distributed object technologies
Earthquake shaking — Finding the "hot spots"
Earthquake ground-motion amplification in Southern California
The variability of PSV response spectra across a dense array deployed during the Northridge aftershock sequence
Ground motion
New USGS map shows where damaging earthquakes are most likely to occur in US
USGS scientists and our partners recently revealed the latest National Seismic Hazard Model, showing that nearly 75% of the United States could experience a damaging earthquake, emphasizing seismic hazards span a significant part of the country.
Science and Products
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A-priori rupture models for Northern California Type-A faults
This appendix describes how a-priori rupture models were developed for the northern California Type-A faults. As described in the main body of this report, and in Appendix G, “a-priori” models represent an initial estimate of the rate of single and multi-segment surface ruptures on each fault. Whether or not a given model is moment balanced (i.e., satisfies section slip-rate data) depends on assumAuthorsChris J. Wills, Ray J. Weldon, Edward H. FieldDevelopment of final a-fault rupture models for WGCEP/ NSHMP Earthquake Rate Model 2
This appendix discusses how we compute the magnitude and rate of earthquake ruptures for the seven Type-A faults (Elsinore, Garlock, San Jacinto, S. San Andreas, N. San Andreas, Hayward-Rodgers Creek, and Calaveras) in the WGCEP/NSHMP Earthquake Rate Model 2 (referred to as ERM 2. hereafter). By definition, Type-A faults are those that have relatively abundant paleoseismic information (e.g., meanAuthorsEdward H. Field, Ray J. Weldon, Thomas Parsons, Chris J. Wills, Timothy E. Dawson, Ross S. Stein, Mark D. PetersenForecasting California's earthquakes— What can we expect in the next 30 years?
In a new comprehensive study, scientists have determined that the chance of having one or more magnitude 6.7 or larger earthquakes in the California area over the next 30 years is greater than 99%. Such quakes can be deadly, as shown by the 1989 magnitude 6.9 Loma Prieta and the 1994 magnitude 6.7 Northridge earthquakes. The likelihood of at least one even more powerful quake of magnitude 7.5 or gAuthorsEdward H. Field, Kevin R. MilnerDocumentation for the 2008 update of the United States National Seismic Hazard Maps
The 2008 U.S. Geological Survey (USGS) National Seismic Hazard Maps display earthquake ground motions for various probability levels across the United States and are applied in seismic provisions of building codes, insurance rate structures, risk assessments, and other public policy. This update of the maps incorporates new findings on earthquake ground shaking, faults, seismicity, and geodesy. ThAuthorsMark D. Petersen, Arthur D. Frankel, Stephen C. Harmsen, Charles S. Mueller, Kathleen M. Haller, Russell L. Wheeler, Robert L. Wesson, Yuehua Zeng, Oliver S. Boyd, David M. Perkins, Nicolas Luco, Edward H. Field, Chris J. Wills, Kenneth S. RukstalesGrid computing in the SCEC community modeling environment
No abstract available.AuthorsP. Maechling, Vipin Gupta, N. Gupta, Edward H. Field, David Okaya, Thomas H JordanHazard calculations for the WGCEP-2002 earthquake forecast using OpenSHA and distributed object technologies
We present seismic-hazard calculations for what is arguably the most sophisticated earthquake forecast ever developed—the model by the 2002 Working Group on California Earthquake Probabilities (2003), or WGCEP-2002 as referred to hereafter. These calculations have been made possible by developments in both OpenSHA (Field et al., 2003) and the Information Technology Research (ITR) Collaboration ofAuthorsEdward H. Field, N. Gupta, Vipin Gupta, Michael L. Blanpied, Phillip J. Maechling, Thomas H. JordanEarthquake shaking — Finding the "hot spots"
A new Southern California Earthquake Center study has quantified how local geologic conditions affect the shaking experienced in an earthquake. The important geologic factors at a site are softness of the rock or soil near the surface and thickness of the sediments above hard bedrock. Even when these 'site effects' are taken into account, however, each earthquake exhibits unique 'hotspots' of anomAuthorsEdward H. Field, Lucile Jones, Tom Jordan, Mark Benthien, Lisa WaldEarthquake ground-motion amplification in Southern California
No abstract available.AuthorsEdward H. FieldThe variability of PSV response spectra across a dense array deployed during the Northridge aftershock sequence
This study addresses the variability of pseudo-velocity response spectra across an array deployed on stiff soil in the San Fernando Valley during the Northridge (Mw 6.7) aftershock sequence. The separation between stations ranged from 0.5 to 5 km, and the aftershock magnitudes ranged from 2.3 to 4.0. We find that 95-percent of observed response spectra are within a factor of 1.9 to 2.6 of the netwAuthorsEdward H. Field, Susan E. HoughGround motion
No abstract available.AuthorsRoger D. Borcherdt, N. C. Donovan, Mehmet Çelebi, A. Shakal, M. Huang, M. Reichle, C. Ventura, T. Cao, R. Bherburne, M. Savage, Robert B. Darragh, C. Petersen, David Boore, W. B. Joyner, E. V. Leyendecker, P. C. Thenhaus, Kimberly W. Campo, Margaret G. Hopper, S.L. Hanson, S. T. Algermissen, David M. Perkins, Susan E. Hough, D. Simpson, A. Lerner-Lam, P.A. Friberg, R. Busby, L. Shengold, M. Tuttle, Edward H. Field, K.H. Jacob, J. Pacheco, C. Estabrook, M. Peterson, D. H. Johnson, Arthur Frankel - Software
- News
New USGS map shows where damaging earthquakes are most likely to occur in US
USGS scientists and our partners recently revealed the latest National Seismic Hazard Model, showing that nearly 75% of the United States could experience a damaging earthquake, emphasizing seismic hazards span a significant part of the country.