Kevin R Milner
Kevin Milner is a Research Geophysicist with the Earthquake Hazards Program.
Kevin develops earthquake forecast models for the USGS Earthquake Hazards Program. His research interests include uncertainty quantification and reduction in seismic hazard analysis, and physics-based earthquake and ground motion simulation. With a background in both computer and geological sciences, he specializes in using high performance computing to tackle complex research problems.
Professional Experience
Research Geophysicist, USGS Geologic Hazards Science Center (2024–Present)
Computer Scientist, Southern California Earthquake Center (2008–2024)
Education and Certifications
PhD (Geological Sciences); University of Southern California, 2020
MS (Geological Sciences); University of Southern California, 2015
BS (Computer Sciences); University of Southern California, 2007
Science and Products
Filter Total Items: 23
The USGS 2023 Conterminous U.S. time‐independent earthquake rupture forecast
We present the 2023 U.S. Geological Survey time‐independent earthquake rupture forecast for the conterminous United States, which gives authoritative estimates of the magnitude, location, and time‐averaged frequency of potentially damaging earthquakes throughout the region. In addition to updating virtually all model components, a major focus has been to provide a better representation of epistemi
Authors
Ned Field, Kevin R. Milner, Alexandra Elise Hatem, Peter M. Powers, Frederick Pollitz, Andrea L. Llenos, Yuehua Zeng, Kaj M. Johnson, Bruce E. Shaw, Devin McPhillips, Jessica Ann Thompson Jobe, Allison Shumway, Andrew J. Michael, Zheng-Kang Shen, Eileen L. Evans, Elizabeth H. Hearn, Charles Mueller, Arthur Frankel, Mark D. Petersen, Christopher DuRoss, Richard W. Briggs, Morgan T. Page, Justin Rubinstein, Julie A Herrick
A comprehensive fault system inversion approach: Methods and application to NSHM23
We present updated inversion‐based fault‐system solutions for the 2023 update to the National Seismic Hazard Model (NSHM23), standardizing earthquake rate model calculations on crustal faults across the western United States. We build upon the inversion methodology used in the Third Uniform California Earthquake Rupture Forecast (UCERF3) to solve for time‐independent rates of earthquakes in an int
Authors
Kevin R. Milner, Ned Field
Enumerating plausible multifault ruptures in complex fault systems with physical constraints
We propose a new model for determining the set of plausible multifault ruptures in an interconnected fault system. We improve upon the rules used in the Third Uniform California Earthquake Rupture Forecast (UCERF3) to increase connectivity and the physical consistency of ruptures. We replace UCERF3’s simple azimuth change rules with new Coulomb favorability metrics and increase the maximum jump di
Authors
Kevin R. Milner, Bruce E. Shaw, Ned Field
The seismic hazard implications of declustering and poisson assumptions inferred from a fully time‐dependent model
We use the Third Uniform California Earthquake Rupture Forecast (UCERF3) epidemic‐type aftershock sequence (ETAS) model (UCERF3‐ETAS) to evaluate the effects of declustering and Poisson assumptions on seismic hazard estimates. Although declustering is necessary to infer the long‐term spatial distribution of earthquake rates, the question is whether it is also necessary to honor the Poisson assumpt
Authors
Ned Field, Kevin R. Milner, Nico Luco
Improvements to the Third Uniform California Earthquake Rupture Forecast ETAS Model (UCERF3‐ETAS)
We describe recent improvements to the Third Uniform California Earthquake Rupture Forecast ETAS Model (UCERF3‐ETAS), which continues to represent our most advanced and complete earthquake forecast in terms of relaxing segmentation assumptions and representing multifault ruptures, elastic‐rebound effects, and spatiotemporal clustering (the latter to represent aftershocks and otherwise triggered ev
Authors
Ned Field, Kevin R. Milner, Morgan T. Page, William H. Savran, Nicholas van der Elst
Toward physics-based nonergodic PSHA: A prototype fully-deterministic seismic hazard model for southern California
We present a nonergodic framework for probabilistic seismic‐hazard analysis (PSHA) that is constructed entirely of deterministic, physical models. The use of deterministic ground‐motion simulations in PSHA calculations is not new (e.g., CyberShake), but prior studies relied on kinematic rupture generators to extend empirical earthquake rupture forecasts. Fully dynamic models, which simulate ruptur
Authors
Kevin R. Milner, Bruce E. Shaw, Christine A. Goulet, Keith B. Richards-Dinger, Scott Callaghan, Thomas H. Jordan, James H. Dieterich, Ned Field
Generalizing the inversion‐based PSHA source model for an interconnected fault system
This article represents a step toward generalizing and simplifying the procedure for constructing an inversion‐based seismic hazard source model for an interconnected fault system, including the specification of adjustable segmentation constraints. A very simple example is used to maximize understandability and to counter the notion that an inversion approach is only applicable when an abundance o
Authors
Ned Field, Kevin R. Milner, Morgan T. Page
Pseudo-prospective evaluation of UCERF3-ETAS forecasts during the 2019 Ridgecrest sequence
The 2019 Ridgecrest sequence provides the first opportunity to evaluate Uniform California Earthquake Rupture Forecast v.3 with epidemic‐type aftershock sequences (UCERF3‐ETAS) in a pseudoprospective sense. For comparison, we include a version of the model without explicit faults more closely mimicking traditional ETAS models (UCERF3‐NoFaults). We evaluate the forecasts with new metrics developed
Authors
William J. Savran, Maximillian J. Werner, W. Marzocchi, David A. Rhoades, David D. Jackson, Kevin R. Milner, Edward H. Field, Andrew J. Michael
Assessing the value of removing earthquake-hazard-related epistemic uncertainties, exemplified using average annual loss in California
To aid in setting scientific research priorities, we assess the potential value of removing each of the epistemic uncertainties currently represented in the US Geological Survey California seismic-hazard model, using average annual loss (AAL) as the risk metric of interest. Given all the uncertainties, represented with logic-tree branches, we find a mean AAL of $3.94 billion. The modal value is 17
Authors
Edward H. Field, Kevin R. Milner, Keith Porter
Operational earthquake forecasting during the 2019 Ridgecrest, California, earthquake sequence with the UCERF3-ETAS model
The first Uniform California Earthquake Rupture Forecast, Version 3–epidemic‐type aftershock sequence (UCERF3‐ETAS) aftershock simulations were running on a high‐performance computing cluster within 33 min of the 4 July 2019 M 6.4 Searles Valley earthquake. UCERF3‐ETAS, an extension of the third Uniform California Earthquake Rupture Forecast (UCERF3), is the first comprehensive, fault‐based, epide
Authors
Kevin R. Milner, Edward H. Field, William H Savran, Morgan T. Page, Thomas H Jordan
A physics-based earthquake simulator replicates seismic hazard statistics across California
Seismic hazard models are important for society, feeding into building codes and hazard mitigation efforts. These models, however, rest on many uncertain assumptions and are difficult to test observationally because of the long recurrence times of large earthquakes. Physics-based earthquake simulators offer a potentially helpful tool, but they face a vast range of fundamental scientific uncertaint
Authors
Bruce E. Shaw, Kevin R. Milner, Edward H. Field, Keith B. Richards-Dinger, Jacquelyn J. Gilchrist, James H. Dieterich, Thomas H. Jordan
Candidate products for operational earthquake forecasting illustrated using the HayWired planning scenario, including one very quick (and not‐so‐dirty) hazard‐map option
In an effort to help address debates on the usefulness of operational earthquake forecasting (OEF), we illustrate a number of OEF products that could be automatically generated in near‐real time. To exemplify, we use an M 7.1 mainshock on the Hayward fault, which is very similar to the U.S. Geological Survey (USGS) HayWired earthquake planning scenario. Given that there is always some background l
Authors
Edward H. Field, Kevin R. Milner
Non-USGS Publications**
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
Operational Earthquake Forecasting – Implementing a Real-Time System for California
It is well know that every earthquake can spawn others (e.g., as aftershocks), and that such triggered events can be large and damaging, as recently demonstrated by L’Aquila, Italy and Christchurch, New Zealand earthquakes. In spite of being an explicit USGS strategic-action priority (http://pubs.usgs.gov/of/2012/1088; page 32), the USGS currently lacks an automated system with which to forecast s
Data Release for the 2023 U.S. 50-State National Seismic Hazard Model - Overview
This data release contains data sets associated with the 2023 50-State National Seismic Hazard Model Update. The 2023 50-State National Seimsic Hazard Model (NSHM) Update includes an update to the NSHMs for the conterminous U.S (CONUS, last updated in 2018), Alaska (AK, last updated in 2007), and Hawaii (last updated in 2001). Data sets include inputs like seismicity catalogs used as input to the
Science and Products
Filter Total Items: 23
The USGS 2023 Conterminous U.S. time‐independent earthquake rupture forecast
We present the 2023 U.S. Geological Survey time‐independent earthquake rupture forecast for the conterminous United States, which gives authoritative estimates of the magnitude, location, and time‐averaged frequency of potentially damaging earthquakes throughout the region. In addition to updating virtually all model components, a major focus has been to provide a better representation of epistemi
Authors
Ned Field, Kevin R. Milner, Alexandra Elise Hatem, Peter M. Powers, Frederick Pollitz, Andrea L. Llenos, Yuehua Zeng, Kaj M. Johnson, Bruce E. Shaw, Devin McPhillips, Jessica Ann Thompson Jobe, Allison Shumway, Andrew J. Michael, Zheng-Kang Shen, Eileen L. Evans, Elizabeth H. Hearn, Charles Mueller, Arthur Frankel, Mark D. Petersen, Christopher DuRoss, Richard W. Briggs, Morgan T. Page, Justin Rubinstein, Julie A Herrick
A comprehensive fault system inversion approach: Methods and application to NSHM23
We present updated inversion‐based fault‐system solutions for the 2023 update to the National Seismic Hazard Model (NSHM23), standardizing earthquake rate model calculations on crustal faults across the western United States. We build upon the inversion methodology used in the Third Uniform California Earthquake Rupture Forecast (UCERF3) to solve for time‐independent rates of earthquakes in an int
Authors
Kevin R. Milner, Ned Field
Enumerating plausible multifault ruptures in complex fault systems with physical constraints
We propose a new model for determining the set of plausible multifault ruptures in an interconnected fault system. We improve upon the rules used in the Third Uniform California Earthquake Rupture Forecast (UCERF3) to increase connectivity and the physical consistency of ruptures. We replace UCERF3’s simple azimuth change rules with new Coulomb favorability metrics and increase the maximum jump di
Authors
Kevin R. Milner, Bruce E. Shaw, Ned Field
The seismic hazard implications of declustering and poisson assumptions inferred from a fully time‐dependent model
We use the Third Uniform California Earthquake Rupture Forecast (UCERF3) epidemic‐type aftershock sequence (ETAS) model (UCERF3‐ETAS) to evaluate the effects of declustering and Poisson assumptions on seismic hazard estimates. Although declustering is necessary to infer the long‐term spatial distribution of earthquake rates, the question is whether it is also necessary to honor the Poisson assumpt
Authors
Ned Field, Kevin R. Milner, Nico Luco
Improvements to the Third Uniform California Earthquake Rupture Forecast ETAS Model (UCERF3‐ETAS)
We describe recent improvements to the Third Uniform California Earthquake Rupture Forecast ETAS Model (UCERF3‐ETAS), which continues to represent our most advanced and complete earthquake forecast in terms of relaxing segmentation assumptions and representing multifault ruptures, elastic‐rebound effects, and spatiotemporal clustering (the latter to represent aftershocks and otherwise triggered ev
Authors
Ned Field, Kevin R. Milner, Morgan T. Page, William H. Savran, Nicholas van der Elst
Toward physics-based nonergodic PSHA: A prototype fully-deterministic seismic hazard model for southern California
We present a nonergodic framework for probabilistic seismic‐hazard analysis (PSHA) that is constructed entirely of deterministic, physical models. The use of deterministic ground‐motion simulations in PSHA calculations is not new (e.g., CyberShake), but prior studies relied on kinematic rupture generators to extend empirical earthquake rupture forecasts. Fully dynamic models, which simulate ruptur
Authors
Kevin R. Milner, Bruce E. Shaw, Christine A. Goulet, Keith B. Richards-Dinger, Scott Callaghan, Thomas H. Jordan, James H. Dieterich, Ned Field
Generalizing the inversion‐based PSHA source model for an interconnected fault system
This article represents a step toward generalizing and simplifying the procedure for constructing an inversion‐based seismic hazard source model for an interconnected fault system, including the specification of adjustable segmentation constraints. A very simple example is used to maximize understandability and to counter the notion that an inversion approach is only applicable when an abundance o
Authors
Ned Field, Kevin R. Milner, Morgan T. Page
Pseudo-prospective evaluation of UCERF3-ETAS forecasts during the 2019 Ridgecrest sequence
The 2019 Ridgecrest sequence provides the first opportunity to evaluate Uniform California Earthquake Rupture Forecast v.3 with epidemic‐type aftershock sequences (UCERF3‐ETAS) in a pseudoprospective sense. For comparison, we include a version of the model without explicit faults more closely mimicking traditional ETAS models (UCERF3‐NoFaults). We evaluate the forecasts with new metrics developed
Authors
William J. Savran, Maximillian J. Werner, W. Marzocchi, David A. Rhoades, David D. Jackson, Kevin R. Milner, Edward H. Field, Andrew J. Michael
Assessing the value of removing earthquake-hazard-related epistemic uncertainties, exemplified using average annual loss in California
To aid in setting scientific research priorities, we assess the potential value of removing each of the epistemic uncertainties currently represented in the US Geological Survey California seismic-hazard model, using average annual loss (AAL) as the risk metric of interest. Given all the uncertainties, represented with logic-tree branches, we find a mean AAL of $3.94 billion. The modal value is 17
Authors
Edward H. Field, Kevin R. Milner, Keith Porter
Operational earthquake forecasting during the 2019 Ridgecrest, California, earthquake sequence with the UCERF3-ETAS model
The first Uniform California Earthquake Rupture Forecast, Version 3–epidemic‐type aftershock sequence (UCERF3‐ETAS) aftershock simulations were running on a high‐performance computing cluster within 33 min of the 4 July 2019 M 6.4 Searles Valley earthquake. UCERF3‐ETAS, an extension of the third Uniform California Earthquake Rupture Forecast (UCERF3), is the first comprehensive, fault‐based, epide
Authors
Kevin R. Milner, Edward H. Field, William H Savran, Morgan T. Page, Thomas H Jordan
A physics-based earthquake simulator replicates seismic hazard statistics across California
Seismic hazard models are important for society, feeding into building codes and hazard mitigation efforts. These models, however, rest on many uncertain assumptions and are difficult to test observationally because of the long recurrence times of large earthquakes. Physics-based earthquake simulators offer a potentially helpful tool, but they face a vast range of fundamental scientific uncertaint
Authors
Bruce E. Shaw, Kevin R. Milner, Edward H. Field, Keith B. Richards-Dinger, Jacquelyn J. Gilchrist, James H. Dieterich, Thomas H. Jordan
Candidate products for operational earthquake forecasting illustrated using the HayWired planning scenario, including one very quick (and not‐so‐dirty) hazard‐map option
In an effort to help address debates on the usefulness of operational earthquake forecasting (OEF), we illustrate a number of OEF products that could be automatically generated in near‐real time. To exemplify, we use an M 7.1 mainshock on the Hayward fault, which is very similar to the U.S. Geological Survey (USGS) HayWired earthquake planning scenario. Given that there is always some background l
Authors
Edward H. Field, Kevin R. Milner
Non-USGS Publications**
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
Operational Earthquake Forecasting – Implementing a Real-Time System for California
It is well know that every earthquake can spawn others (e.g., as aftershocks), and that such triggered events can be large and damaging, as recently demonstrated by L’Aquila, Italy and Christchurch, New Zealand earthquakes. In spite of being an explicit USGS strategic-action priority (http://pubs.usgs.gov/of/2012/1088; page 32), the USGS currently lacks an automated system with which to forecast s
Data Release for the 2023 U.S. 50-State National Seismic Hazard Model - Overview
This data release contains data sets associated with the 2023 50-State National Seismic Hazard Model Update. The 2023 50-State National Seimsic Hazard Model (NSHM) Update includes an update to the NSHMs for the conterminous U.S (CONUS, last updated in 2018), Alaska (AK, last updated in 2007), and Hawaii (last updated in 2001). Data sets include inputs like seismicity catalogs used as input to the