I have spent much of my career working to understand, assess, and mitigate the hazards of volcanic ash.
To understand the nature of the hazard, I have studied tephra deposits in the field and designed experiments to generate volcanic ash in the laboratory. I also develop and use models that simulate the ascent of magma in conduits, rise of ash in volcanic plumes, and downwind movement of ash clouds. I have been involved in the development and application of several models that simulate these processes.
I have worked with emergency managers, Volcanic Ash Advisory Centers, and specialists from more than a dozen volcano observatories around the world to improve the accuracy of volcanic ash forecasts, both for aviation safety and for ground-based communities. From 2010-2020 I served as co-chair of the World Meteorological Organization’s Volcanic Ash Scientific Advisory Group, an expert panel dedicated to advising Volcanic Ash Advisory Centers on the science and practice of volcanic ash-cloud detection and forecasting.
My professional life began as a mud logger working on the North Slope of Alaska in 1980-81. While studying for my master’s degree at Stanford in 1982-84, I worked part time for the Tectonophysics branch of the USGS in Menlo Park, California, where I assisted with hydraulic fracturing stress measurements, and studied the growth of fractures and the development of breakouts, i.e. stress-induced zones of failure, around boreholes in sandstone.
My Ph.D. work at Stanford, from 1984-1988, under Professor David Pollard, involved field and laboratory study of the growth of surface faults above a shallow dike in Long Valley Caldera, California. A second half of this study focused on how the dike heated groundwater that erupted to produce several large explosion craters, the Inyo Craters, north of the town of Mammoth Lakes.
After completing my Ph.D., I worked from 1988-1990 as a post-doctoral researcher in the Geophysics Institute at the University of Karlsruhe, Germany. My tasks included compiling data for the European part of a World Stress Map project, and examining the state of stress at a deep drillhole site in northern Bavaria.
At the Cascades Volcano Observatory, from 1990 through the late 2000s, I concentrated on the role of water in the style and timing of eruptions. This work involved, for example, an examination of correlations between rainfall and gas explosions at Mount St. Helens; on the conditions that produced explosive phreatomagmatic eruptions at Kilauea, and effects of turbulent water-magma mixing on eruptive style.
Since the late 2000s, I have been involved primarily in volcanic ash hazards, as described above.
Education and Certifications
1988 Ph.D. Geomechanics, Stanford University
1984 M.S. Engineering Geology, Stanford University
1980 B.S. Geology, University of California, Davis (cum Laude)
Affiliations and Memberships*
Fellow, Geological Society of America
Member, American Geophysical Union
Member, International Association of Volcanology and Chemistry of the Earth's Interior (IAVCEI)
Member, American Meteorological Society
Member, American Association
Honors and Awards
2018: Fellow, Geological Society of America
Abstracts and Presentations
2021: “Comparing the hazards of wildfire smoke and volcanic ash in the Pacific Northwest”, invited talk in the Cascadia Wildfire and Urban Smoke seminar series, sponsored by Portland State University and the Cascadia Innovation Corridor Iniative (search for it on YouTube)
2020: “Protecting air travel from volcanic ash in the coming decade”, invited talk V08-15 at 2020 American Geophysical Union Fall Meeting.
2016: “Forecasting Ashfall Impacts from a Yellowstone Supereruption”, USGS Menlo Park Public Lecture, May 26, 2016, https://www.usgs.gov/media/videos/forecasting-ashfall-impacts-a-yellowstone-supereruption
Science and Products
Model simulation output from a magnitude 7 eruption: the distal Mazama tephra
This data release contains model input and output for 57 simulations of tephra dispersal during the 7.8 ka Mazama eruption. Data were generated during in preparation of the following paper:
Buckland HM, Mastin L, Engwell S, Cashman K (2022 (in pess)) Modelling the transport and deposition of ash following a Magnitude 7 eruption: the distal Mazama tephra. Bull Volcanol. 84(9):87. https://doi.org/1
Data used to develop a probabilistic assessment of tephra-fall hazards at Hanford, Washington
Data in this data release contain Model input and output for simulations used to estimate the amount of tephra that could fall on the Hanford nuclear waste repository. The results of that study were written up in the report: Mastin, L.G., Van Eaton, A.E., and Schwaiger, H.F., 2020 A Probabilistic Assessment of Tephra-Fall Hazards at Hanford, Washington, from a Future Eruption of Mount St. Helens,
Observations and model simulations of umbrella-cloud growth during eruptions of Mount Pinatubo (Philippines, June 15, 1991), Kelud Volcano (Indonesia, February 14, 2014), and Calbuco Volcano (Chile, April 22-23, 2015)
Model output to accompany the paper "Comparing Simulations of Umbrella-Cloud Growth and Ash Transport with Observations from Pinatubo, Kelud, and Calbuco Volcanoes", by L.G. Mastin and Alexa Van Eaton, published by the journal Atmosphere. The data release includes model input and output used to generate figures in the paper. Reference: Mastin, L.G., and Van Eaton, A.R., 2020, Comparing Simulation
Plots of Wind Patterns of the World's Volcanoes
This product includes rose diagrams and tables of wind patterns at volcanoes listed in the Smithsonian Institution's Volcanoes of the World Database. At each volcano, the speed and direction of wind above the volcano were read from output of the NCEP/NCAR Reanalysis 1 model, at twice-daily intervals from January 1, 1990 to December 28, 2009. These results were then plotted as 20 wind rose diagra
Filter Total Items: 52
A one-dimensional volcanic plume model for predicting ash aggregation
During explosive volcanic eruptions, volcanic ash is ejected into the atmosphere, impacting aircraft safety and downwind communities. These volcanic clouds tend to be dominated by fine ash (<63 μm in diameter), permitting transport over hundreds to thousands of kilometers. However, field observations show that much of this fine ash aggregates into clusters or pellets with faster settling velocitie
Authors
Davis W. Hoffman, Larry G. Mastin, Alexa R. Van Eaton, Stephen A. Solovitz, Raul B. Cal, John K. Eaton
New insights into the relationship between mass eruption rate and volcanic column height based on the IVESPA dataset
Rapid and simple estimation of the mass eruption rate (MER) from column height is essential for real-time volcanic hazard management and reconstruction of past explosive eruptions. Using 134 eruptive events from the new Independent Volcanic Eruption Source Parameter Archive (IVESPA, v1.0), we explore empirical MER-height relationships for four measures of column height: spreading level, sulfur dio
Authors
Thomas J. Aubry, Samantha Engwell, Costanza Bonadonna, Larry G. Mastin, Guillaume Carazzo, Alexa R. Van Eaton, David E. Jessop, Roy G. Grainger, Simona Scollo, Isabelle A Taylor, A. Mark Jellinek, Anja Schmidt, Sebastien Biass, Mathieu Gouhier
Flow development and entrainment in turbulent particle-laden jets
Explosive eruptions expel volcanic gases and particles at high pressures and velocities. Within this multiphase fluid, small ash particles affect the flow dynamics, impacting mixing, entrainment, turbulence, and aggregation. To examine the role of turbulent particle behavior, we conducted an analogue experiment using a particle-laden jet. We used compressed air as the carrier fluid, considering tu
Authors
Laura K. Shannon, Bianca Viggiano, Raul Bayoan Cal, Larry G. Mastin, Alexa R. Van Eaton, Stephen A. Solovitz
A review of common natural disasters as analogs for asteroid impact effects and cascading hazards
Modern civilization has no collective experience with possible wide-ranging effects from a medium-sized asteroid impactor. Currently, modeling efforts that predict initial effects from a meteor impact or airburst provide needed information for initial preparation and evacuation plans, but longer-term cascading hazards are not typically considered. However, more common natural disasters, such as vo
Authors
Timothy N. Titus, D. G. Robertson, Joel B. Sankey, Larry G. Mastin, Francis K. Rengers
Understanding and modeling tephra transport: Lessons learned from the 18 May 1980 eruption of Mount St. Helens
Discoveries made during the 18 May 1980 eruption of Mount St. Helens advanced our understanding of tephra transport and deposition in fundamental ways. The eruption enabled detailed, quantitative observations of downwind cloud movement and particle sedimentation, along with the dynamics of co-pyroclastic-density current (PDC) clouds lofted from ground-hugging currents. The deposit was mapped and s
Authors
Larry G. Mastin, Steven Carey, Alexa R. Van Eaton, Julia Eychenne, R.S.J. Sparks
Modelling the transport and deposition of ash following a magnitude 7 eruption: The distal Mazama tephra
Volcanic ash transport and dispersion models (VATDMs) are necessary for forecasting tephra dispersal during volcanic eruptions and are a useful tool for estimating the eruption source parameters (ESPs) of prehistoric eruptions. Here we use Ash3D, an Eulerian VATDM, to simulate the tephra deposition from the ~ 7.7 ka climactic eruption of Mount Mazama. We investigate how best to apply a VATDM using
Authors
Hannah Maeve Buckland, Larry G. Mastin, Samantha Engwell, Katharine V. Cashman
Forecasting and communicating the dispersion and fallout of ash during volcanic eruptions: lessons from the September 20, 2020 eruptive pulse at Sangay volcano, Ecuador
Volcanic ash is a hazard to human health and activities. Accurate and timely forecasts coupled with effective communication about the dispersion and fallout of volcanic ash during explosive events are essential to reduce impacts on local communities and limit economic losses. In this study, we present the first detailed description of an eruptive pulse at Sangay volcano and its eruption source par
Authors
Benjamin Bernard, Pablo Samaniego, Larry G. Mastin, Stephen Hernandez, Gerardo Pino, Jamie Kibler, Marjorie Encalada, Silvano Hidalgo, Nicole Vizuete
Progress in protecting air travel from volcanic ash clouds
The Eyjafjallajökull eruption of 2010 demonstrated the far-reaching impact of ash clouds and the vulnerability of our jet-based society to them, prompting a review of procedures to detect, warn, and forecast ash cloud hazards to aviation. The years since 2010 have seen marked improvements in satellite technology, more accurate ash-dispersion models that integrate simulations with observations, and
Authors
Larry G. Mastin, Michael J. Pavolonis, Samantha Engwell, Rory Clarkson, Claire Witham, Greg Brock, Ian Lisk, Marianne C. Guffanti, Andrew C. Tupper, David Schneider, Frances Beckett, Thomas J. Casadevall, Graham Rennie
Evaluating the state-of-the-art in remote volcanic eruption characterization Part I: Raikoke volcano, Kuril Islands
Raikoke, a small, unmonitored volcano in the Kuril Islands, erupted in June 2019. We integrate data from satellites (including Sentinel-2, TROPOMI, MODIS, Himawari-8), the International Monitoring System (IMS) infrasound network, and global lightning detection network (GLD360) with information from local authorities and social media to retrospectively characterize the eruptive sequence and improve
Authors
Kathleen McKee, Cassandra Marie Smith, Kevin Reath, Eveanjelene Snee, Sean Maher, Robin S. Matoza, Simon A Carn, Larry G. Mastin, Kyle R. Anderson, David Damby, Diana Roman, Artem Degterev, Alexander Rybin, Marina Chibisova, Jelle D. Assink, Rodrigo de Negri Levia, Anna Perttu
Evaluating the state-of-the-art in remote volcanic eruption characterization Part II: Ulawun volcano, Papua New Guinea
Retrospective eruption characterization is valuable for advancing our understanding of volcanic systems and evaluating our observational capabilities, especially with remote technologies (defined here as a space-borne system or non-local, ground-based instrumentation which include regional and remote infrasound sensors). In June 2019, the open-system Ulawun volcano, Papua New Guinea, produced a VE
Authors
Kathleen McKee, Cassandra Marie Smith, Kevin Reath, Eveanjelene Snee, Sean Maher, Robin S. Matoza, Simon A Carn, Diana Roman, Larry G. Mastin, Kyle R. Anderson, David Damby, Ima Itikarai, Kila Mulina, Steve Saunders, Jelle D. Assink, Rodrigo de Negri Levia, Anna Perttu
The Independent Volcanic Eruption Source Parameter Archive (IVESPA, version 1.0): A new observational database to support explosive eruptive column model validation and development
Eruptive column models are powerful tools for investigating the transport of volcanic gas and ash, reconstructing past explosive eruptions, and simulating future hazards. However, the evaluation of these models is challenging as it requires independent estimates of the main model inputs (e.g. mass eruption rate) and outputs (e.g. column height). There exists no database of independently estimated
Authors
Thomas J Aubry, Samantha Engwell, Costanza Bonadonna, Guillaume Carazzo, Simona Scollo, Alexa R. Van Eaton, Isabelle A Taylor, David Jessop, Julia Eychenne, Mathieu Gouhier, Larry G. Mastin, Kristi L. Wallace, Sébastien Biass, Marcus Bursik, Roy G Grainger, Mark Jellinek, Anja Schmidt
Asteroid impacts - downwind and downstream effects
For this abstract, we have selected an impact location, consistent with the PDC2021 initial scenario [1], in the San Juan Mountains, in southwestern Colorado. This is a low-density population area but is part of the watershed system within the Colorado River basin, a major source for water and power for the southwestern United States. Several large cities and major airports are potentially downwin
Authors
Timothy N. Titus, D. G. Robertson, Joel B. Sankey, Larry G. Mastin
plumeria PMAP software release 1.0.3
The PMAP tool is a one-dimensional plume model that predicts ash aggregation within an erupting volcanic plume. The tool was developed by D. W. Hoffman at Stanford, extending from the Plumeria model written by L. G. Mastin at USGS CVO. The code operates using Matlab.
The purpose of this repository is to present the code used in the following publication, currently under review at Journal of Geop
Ash3D provides forecasts of ash clouds and ashfall.
Ash 3D is a three-dimensional simulation of volcanic-ash dispersion that uses time-varying wind fields and other meteorological properties to calculate where airborne ash is transported under current or historical atmospheric conditions
Science and Products
- Data
Model simulation output from a magnitude 7 eruption: the distal Mazama tephra
This data release contains model input and output for 57 simulations of tephra dispersal during the 7.8 ka Mazama eruption. Data were generated during in preparation of the following paper: Buckland HM, Mastin L, Engwell S, Cashman K (2022 (in pess)) Modelling the transport and deposition of ash following a Magnitude 7 eruption: the distal Mazama tephra. Bull Volcanol. 84(9):87. https://doi.org/1Data used to develop a probabilistic assessment of tephra-fall hazards at Hanford, Washington
Data in this data release contain Model input and output for simulations used to estimate the amount of tephra that could fall on the Hanford nuclear waste repository. The results of that study were written up in the report: Mastin, L.G., Van Eaton, A.E., and Schwaiger, H.F., 2020 A Probabilistic Assessment of Tephra-Fall Hazards at Hanford, Washington, from a Future Eruption of Mount St. Helens,Observations and model simulations of umbrella-cloud growth during eruptions of Mount Pinatubo (Philippines, June 15, 1991), Kelud Volcano (Indonesia, February 14, 2014), and Calbuco Volcano (Chile, April 22-23, 2015)
Model output to accompany the paper "Comparing Simulations of Umbrella-Cloud Growth and Ash Transport with Observations from Pinatubo, Kelud, and Calbuco Volcanoes", by L.G. Mastin and Alexa Van Eaton, published by the journal Atmosphere. The data release includes model input and output used to generate figures in the paper. Reference: Mastin, L.G., and Van Eaton, A.R., 2020, Comparing SimulationPlots of Wind Patterns of the World's Volcanoes
This product includes rose diagrams and tables of wind patterns at volcanoes listed in the Smithsonian Institution's Volcanoes of the World Database. At each volcano, the speed and direction of wind above the volcano were read from output of the NCEP/NCAR Reanalysis 1 model, at twice-daily intervals from January 1, 1990 to December 28, 2009. These results were then plotted as 20 wind rose diagra - Publications
Filter Total Items: 52
A one-dimensional volcanic plume model for predicting ash aggregation
During explosive volcanic eruptions, volcanic ash is ejected into the atmosphere, impacting aircraft safety and downwind communities. These volcanic clouds tend to be dominated by fine ash (<63 μm in diameter), permitting transport over hundreds to thousands of kilometers. However, field observations show that much of this fine ash aggregates into clusters or pellets with faster settling velocitieAuthorsDavis W. Hoffman, Larry G. Mastin, Alexa R. Van Eaton, Stephen A. Solovitz, Raul B. Cal, John K. EatonNew insights into the relationship between mass eruption rate and volcanic column height based on the IVESPA dataset
Rapid and simple estimation of the mass eruption rate (MER) from column height is essential for real-time volcanic hazard management and reconstruction of past explosive eruptions. Using 134 eruptive events from the new Independent Volcanic Eruption Source Parameter Archive (IVESPA, v1.0), we explore empirical MER-height relationships for four measures of column height: spreading level, sulfur dioAuthorsThomas J. Aubry, Samantha Engwell, Costanza Bonadonna, Larry G. Mastin, Guillaume Carazzo, Alexa R. Van Eaton, David E. Jessop, Roy G. Grainger, Simona Scollo, Isabelle A Taylor, A. Mark Jellinek, Anja Schmidt, Sebastien Biass, Mathieu GouhierFlow development and entrainment in turbulent particle-laden jets
Explosive eruptions expel volcanic gases and particles at high pressures and velocities. Within this multiphase fluid, small ash particles affect the flow dynamics, impacting mixing, entrainment, turbulence, and aggregation. To examine the role of turbulent particle behavior, we conducted an analogue experiment using a particle-laden jet. We used compressed air as the carrier fluid, considering tuAuthorsLaura K. Shannon, Bianca Viggiano, Raul Bayoan Cal, Larry G. Mastin, Alexa R. Van Eaton, Stephen A. SolovitzA review of common natural disasters as analogs for asteroid impact effects and cascading hazards
Modern civilization has no collective experience with possible wide-ranging effects from a medium-sized asteroid impactor. Currently, modeling efforts that predict initial effects from a meteor impact or airburst provide needed information for initial preparation and evacuation plans, but longer-term cascading hazards are not typically considered. However, more common natural disasters, such as voAuthorsTimothy N. Titus, D. G. Robertson, Joel B. Sankey, Larry G. Mastin, Francis K. RengersUnderstanding and modeling tephra transport: Lessons learned from the 18 May 1980 eruption of Mount St. Helens
Discoveries made during the 18 May 1980 eruption of Mount St. Helens advanced our understanding of tephra transport and deposition in fundamental ways. The eruption enabled detailed, quantitative observations of downwind cloud movement and particle sedimentation, along with the dynamics of co-pyroclastic-density current (PDC) clouds lofted from ground-hugging currents. The deposit was mapped and sAuthorsLarry G. Mastin, Steven Carey, Alexa R. Van Eaton, Julia Eychenne, R.S.J. SparksModelling the transport and deposition of ash following a magnitude 7 eruption: The distal Mazama tephra
Volcanic ash transport and dispersion models (VATDMs) are necessary for forecasting tephra dispersal during volcanic eruptions and are a useful tool for estimating the eruption source parameters (ESPs) of prehistoric eruptions. Here we use Ash3D, an Eulerian VATDM, to simulate the tephra deposition from the ~ 7.7 ka climactic eruption of Mount Mazama. We investigate how best to apply a VATDM usingAuthorsHannah Maeve Buckland, Larry G. Mastin, Samantha Engwell, Katharine V. CashmanForecasting and communicating the dispersion and fallout of ash during volcanic eruptions: lessons from the September 20, 2020 eruptive pulse at Sangay volcano, Ecuador
Volcanic ash is a hazard to human health and activities. Accurate and timely forecasts coupled with effective communication about the dispersion and fallout of volcanic ash during explosive events are essential to reduce impacts on local communities and limit economic losses. In this study, we present the first detailed description of an eruptive pulse at Sangay volcano and its eruption source parAuthorsBenjamin Bernard, Pablo Samaniego, Larry G. Mastin, Stephen Hernandez, Gerardo Pino, Jamie Kibler, Marjorie Encalada, Silvano Hidalgo, Nicole VizueteProgress in protecting air travel from volcanic ash clouds
The Eyjafjallajökull eruption of 2010 demonstrated the far-reaching impact of ash clouds and the vulnerability of our jet-based society to them, prompting a review of procedures to detect, warn, and forecast ash cloud hazards to aviation. The years since 2010 have seen marked improvements in satellite technology, more accurate ash-dispersion models that integrate simulations with observations, andAuthorsLarry G. Mastin, Michael J. Pavolonis, Samantha Engwell, Rory Clarkson, Claire Witham, Greg Brock, Ian Lisk, Marianne C. Guffanti, Andrew C. Tupper, David Schneider, Frances Beckett, Thomas J. Casadevall, Graham RennieEvaluating the state-of-the-art in remote volcanic eruption characterization Part I: Raikoke volcano, Kuril Islands
Raikoke, a small, unmonitored volcano in the Kuril Islands, erupted in June 2019. We integrate data from satellites (including Sentinel-2, TROPOMI, MODIS, Himawari-8), the International Monitoring System (IMS) infrasound network, and global lightning detection network (GLD360) with information from local authorities and social media to retrospectively characterize the eruptive sequence and improveAuthorsKathleen McKee, Cassandra Marie Smith, Kevin Reath, Eveanjelene Snee, Sean Maher, Robin S. Matoza, Simon A Carn, Larry G. Mastin, Kyle R. Anderson, David Damby, Diana Roman, Artem Degterev, Alexander Rybin, Marina Chibisova, Jelle D. Assink, Rodrigo de Negri Levia, Anna PerttuEvaluating the state-of-the-art in remote volcanic eruption characterization Part II: Ulawun volcano, Papua New Guinea
Retrospective eruption characterization is valuable for advancing our understanding of volcanic systems and evaluating our observational capabilities, especially with remote technologies (defined here as a space-borne system or non-local, ground-based instrumentation which include regional and remote infrasound sensors). In June 2019, the open-system Ulawun volcano, Papua New Guinea, produced a VEAuthorsKathleen McKee, Cassandra Marie Smith, Kevin Reath, Eveanjelene Snee, Sean Maher, Robin S. Matoza, Simon A Carn, Diana Roman, Larry G. Mastin, Kyle R. Anderson, David Damby, Ima Itikarai, Kila Mulina, Steve Saunders, Jelle D. Assink, Rodrigo de Negri Levia, Anna PerttuThe Independent Volcanic Eruption Source Parameter Archive (IVESPA, version 1.0): A new observational database to support explosive eruptive column model validation and development
Eruptive column models are powerful tools for investigating the transport of volcanic gas and ash, reconstructing past explosive eruptions, and simulating future hazards. However, the evaluation of these models is challenging as it requires independent estimates of the main model inputs (e.g. mass eruption rate) and outputs (e.g. column height). There exists no database of independently estimatedAuthorsThomas J Aubry, Samantha Engwell, Costanza Bonadonna, Guillaume Carazzo, Simona Scollo, Alexa R. Van Eaton, Isabelle A Taylor, David Jessop, Julia Eychenne, Mathieu Gouhier, Larry G. Mastin, Kristi L. Wallace, Sébastien Biass, Marcus Bursik, Roy G Grainger, Mark Jellinek, Anja SchmidtAsteroid impacts - downwind and downstream effects
For this abstract, we have selected an impact location, consistent with the PDC2021 initial scenario [1], in the San Juan Mountains, in southwestern Colorado. This is a low-density population area but is part of the watershed system within the Colorado River basin, a major source for water and power for the southwestern United States. Several large cities and major airports are potentially downwinAuthorsTimothy N. Titus, D. G. Robertson, Joel B. Sankey, Larry G. Mastin - Software
plumeria PMAP software release 1.0.3
The PMAP tool is a one-dimensional plume model that predicts ash aggregation within an erupting volcanic plume. The tool was developed by D. W. Hoffman at Stanford, extending from the Plumeria model written by L. G. Mastin at USGS CVO. The code operates using Matlab. The purpose of this repository is to present the code used in the following publication, currently under review at Journal of GeopAsh3D provides forecasts of ash clouds and ashfall.
Ash 3D is a three-dimensional simulation of volcanic-ash dispersion that uses time-varying wind fields and other meteorological properties to calculate where airborne ash is transported under current or historical atmospheric conditions
- News
*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government