Michelle L. Coombs, Ph.D.
Michelle Coombs is a Supervisory Research Geologist with the U.S. Geological Survey Volcanic Science Center. At the Alaska Volcano Observatory, she works on a wide variety of topics related to active volcanism, volcano geology, and volcanic hazards. She also serves as chief of the Volcano Hazards Assessment Project.
Professional Experience
2023–present: Supervisory Research Geologist, Alaska Volcano Observatory, Volcano Science Center, U.S. Geological Survey, Anchorage, AK
2016–2023: Scientist-in-Charge, Alaska Volcano Observatory
2004–2016: Research Geologist, Alaska Volcano Observatory
2001–2004: Research Geologist, Volcano Hazards Team, U.S. Geological Survey, Menlo Park CA
Education and Certifications
B.A., Geology, Williams College, 1994
Ph.D., Geology, University of Alaska Fairbanks, 2001
Science and Products
Ahyi Seamount Eruption Chronology Ahyi Seamount Eruption Chronology
This presents the observational chronology of eruptions of Ahyi Seamount. Data include USGS information products released for these eruptions, a summary of plumes of discolored water noted in moderate to high resolution satellite imagery back to 1999, and hydroacoustic detections from the direction of Ahyi Seamount from the Wake Island hydrophone array back to 2015.
Digital geologic map data for Semisopochnoi Island, Alaska Digital geologic map data for Semisopochnoi Island, Alaska
This dataset contains digital data that were used for the creation of a geologic map shown in Figure 3 in USGS SIR 2017-5150; Postglacial Eruptive History and Geochemistry of Semisopochnoi Volcano, Western Aleutian Islands, Alaska by Coombs, M.L. and others. The map shows the generalized geology of the island and the locations of stations occupied during field work conducted in the...
Aleutian Arc Fluid Geochemical Data Aleutian Arc Fluid Geochemical Data
This report contains the chemical and isotopic data from thermal waters and gases collected from the Aleutian Arc over the past 20 years, where such data remain unpublished or only published in part.
Geologic map of Mount Gareloi, Gareloi Island, Alaska Geologic map of Mount Gareloi, Gareloi Island, Alaska
Gareloi Island (lat 51.7° N., long 178.8° W.) is located in the Delarof Islands group of the Aleutian Islands, approximately 2,000 km west-southwest of Anchorage and 150 km west of Adak, the westernmost town in Alaska. This small (~8- x 10-km diam), uninhabited island is constructed exclusively of eruptive products from Mount Gareloi volcano, a Pleistocene and Holocene, steep-sided...
Filter Total Items: 79
Examples of eruption response teams from the Alaska Volcano Observatory Examples of eruption response teams from the Alaska Volcano Observatory
During times of eruption response, volcano observatories need to organize themselves differently than during normal operations. The number of formal operational roles grows to ensure that critical responsibilities are covered, including management of all activities at the observatory as well as increased staffing to ensure proper surveillance of data and issuance of timely notices and...
Authors
Michelle L. Coombs, Kristi L. Wallace, Ronni Grapenthin, Jordan Edward Lubbers, Tom Murray
Mount Spurr Volcano Mount Spurr Volcano
No abstract available.
Authors
Kristi L. Wallace, Christopher F. Waythomas, Michelle L. Coombs, A.M. Nastan
Insights on arc magmatic systems drawn from natural melt inclusions and crystallization experiments at PH2O=800 MPa under oxidizing conditions Insights on arc magmatic systems drawn from natural melt inclusions and crystallization experiments at PH2O=800 MPa under oxidizing conditions
Whole rock compositions at Buldir Volcano, western Aleutian arc, record a strong, continuous trend of iron depletion with decreasing MgO, classically interpreted as a calc-alkaline liquid line of descent. In contrast, olivine-hosted melt inclusions have higher total iron (FeO*) than whole rocks and show little change in FeO* with decreasing MgO. To investigate this discrepancy and...
Authors
Janine L. Andrys, Elizabeth Cottrell, Katherine A. Kelley, Laura E. Waters, Michelle L. Coombs
Introduction to recommended capabilities and instrumentation for volcano monitoring in the United States Introduction to recommended capabilities and instrumentation for volcano monitoring in the United States
Authors
Ashton F. Flinders, Jacob B. Lowenstern, Michelle L. Coombs, Michael P. Poland
Recommended capabilities and instrumentation for volcano monitoring in the United States Recommended capabilities and instrumentation for volcano monitoring in the United States
The National Volcano Early Warning System (NVEWS) was authorized and partially funded by the U.S. Government in 2019. In response, the U.S. Geological Survey (USGS) Volcano Hazards Program asked its scientists to reflect on and summarize their views of best practices for volcano monitoring. The goal was to review and update the recommendations of a previous report (Moran and others, 2008...
From field station to forecast: Managing data at the Alaska Volcano Observatory From field station to forecast: Managing data at the Alaska Volcano Observatory
The Alaska Volcano Observatory (AVO) uses multidisciplinary data to monitor and study dozens of active and potentially active volcanoes. Here, we provide an overview of internally and externally generated data types, tools and resources used in their management, and challenges faced. Data sources include the following: (1) a multiparameter (seismic, infrasound, GNSS, web cameras) ground...
Authors
Michelle L. Coombs, Cheryl Cameron, Hannah R. Dietterich, Eleanor Boyce, Aaron Wech, Ronni Grapenthin, Kristi L. Wallace, Thomas Parker, Taryn Lopez, Scott Crass, David Fee, Matthew M. Haney, Dane M. Ketner, Matthew W. Loewen, John J. Lyons, Jenny Sha Nakai, John A. Power, Steven M Botnick, Israel Brewster, Max L. Enders, Dain Harmon, Peter J. Kelly, Michael J. Randall
Probabilistic source classification of large tephra producing eruptions using supervised machine learning: An example from the Alaska-Aleutian arc Probabilistic source classification of large tephra producing eruptions using supervised machine learning: An example from the Alaska-Aleutian arc
Alaska contains over 130 volcanoes and volcanic fields that have been active within the last 2 million years. Of these, roughly 90 have erupted during the Holocene, with many characterized by at least one large explosive eruption. These large tephra-producing eruptions (LTPEs) generate orders of magnitude more erupted material than a “typical” arc explosive eruption and distribute ash...
Authors
Jordan Edward Lubbers, Matthew W. Loewen, Kristi L. Wallace, Michelle L. Coombs, Jason A. Addison
Coordinating science during an eruption: Lessons from the 2020–2021 Kīlauea volcanic eruption Coordinating science during an eruption: Lessons from the 2020–2021 Kīlauea volcanic eruption
Data collected during well-observed eruptions can lead to dramatic increases in our understanding of volcanic processes. However, the necessary prioritization of public safety and hazard mitigation during a crisis means that scientific opportunities may be sacrificed. Thus, maximizing the scientific gains from eruptions requires improved planning and coordinating science activities among
Authors
Kari M. Cooper, Kyle R. Anderson, Kathy Cashman, Michelle L. Coombs, Hannah R. Dietterich, Tobias Fischer, Bruce F. Houghton, Ingrid A. Johanson, Kendra J. Lynn, Michael Manga, Christelle Wauthier
Eruption of compositionally heterogeneous andesites from a complex storage region during the 2006 eruption of Augustine Volcano Eruption of compositionally heterogeneous andesites from a complex storage region during the 2006 eruption of Augustine Volcano
Despite the common occurrence of heterogeneous andesitic eruptions, few studies have investigated the compositional effects on microlite crystallization and vesiculation in co-erupted natural samples. In 2006, Augustine Volcano erupted compositionally heterogeneous andesites that range from 56.4 to 63.3 wt% SiO2 and include two endmember lithologic groups: low-silica andesite (LSA) and...
Authors
Mary Catherine Benage, Heather M. Wright, Michelle L. Coombs
Generation of calc-alkaline magmas during crystallization at high oxygen fugacity: An experimental and petrologic study of tephras from Buldir Volcano, western Aleutian Arc, Alaska, USA Generation of calc-alkaline magmas during crystallization at high oxygen fugacity: An experimental and petrologic study of tephras from Buldir Volcano, western Aleutian Arc, Alaska, USA
Despite agreement that calc-alkaline volcanism occurs at subduction zones and is responsible for the genesis of continental landmasses, there is no consensus on the source of the Fe-depleted signature hallmark to calc-alkaline volcanism. In this study, we utilize mafic tephras collected from Buldir Volcano to address the genesis of strongly calc-alkaline volcanic rocks (those with a low...
Authors
Laura Waters, Elizabeth Cottrell, Michelle L. Coombs, Katherine A. Kelley
The eruptive history, magmatic evolution, and influence of glacial ice at long-lived Akutan volcano, eastern Aleutian Islands, Alaska, USA The eruptive history, magmatic evolution, and influence of glacial ice at long-lived Akutan volcano, eastern Aleutian Islands, Alaska, USA
New 40Ar/39Ar and whole-rock geochemical data are used to develop a detailed eruptive chronology for Akutan volcano, Akutan Island, Alaska, USA, in the eastern Aleutian island arc. Akutan Island (166°W, 54.1°N) is the site of long-lived volcanism and the entire island comprises volcanic rocks as old as 3.3 Ma. Our current study is on the 225 km2 western half of the island, where our...
Authors
Michelle L. Coombs, Brian Jicha
U.S. Geological Survey 2018 Kīlauea Volcano eruption response in Hawai'i—After-action review U.S. Geological Survey 2018 Kīlauea Volcano eruption response in Hawai'i—After-action review
The 2018 Kīlauea Volcano eruption lasted 107 days, and now ranks as the most destructive event at Kilauea since 1790, and as one of the most costly volcanic disasters in U.S. history. Multiple simultaneous hazard events unfolded, including sustained seismic activity leading to collapse at the summit of Halema'uma'u crater and severe damage to the HVO facility, with additional eruption of...
Authors
Dee M. Williams, Vic F. Avery, Michelle L. Coombs, Dale A. Cox, Lief R. Horwitz, Sara K. McBride, Ryan J. McClymont, Seth C. Moran
Science and Products
Ahyi Seamount Eruption Chronology Ahyi Seamount Eruption Chronology
This presents the observational chronology of eruptions of Ahyi Seamount. Data include USGS information products released for these eruptions, a summary of plumes of discolored water noted in moderate to high resolution satellite imagery back to 1999, and hydroacoustic detections from the direction of Ahyi Seamount from the Wake Island hydrophone array back to 2015.
Digital geologic map data for Semisopochnoi Island, Alaska Digital geologic map data for Semisopochnoi Island, Alaska
This dataset contains digital data that were used for the creation of a geologic map shown in Figure 3 in USGS SIR 2017-5150; Postglacial Eruptive History and Geochemistry of Semisopochnoi Volcano, Western Aleutian Islands, Alaska by Coombs, M.L. and others. The map shows the generalized geology of the island and the locations of stations occupied during field work conducted in the...
Aleutian Arc Fluid Geochemical Data Aleutian Arc Fluid Geochemical Data
This report contains the chemical and isotopic data from thermal waters and gases collected from the Aleutian Arc over the past 20 years, where such data remain unpublished or only published in part.
Geologic map of Mount Gareloi, Gareloi Island, Alaska Geologic map of Mount Gareloi, Gareloi Island, Alaska
Gareloi Island (lat 51.7° N., long 178.8° W.) is located in the Delarof Islands group of the Aleutian Islands, approximately 2,000 km west-southwest of Anchorage and 150 km west of Adak, the westernmost town in Alaska. This small (~8- x 10-km diam), uninhabited island is constructed exclusively of eruptive products from Mount Gareloi volcano, a Pleistocene and Holocene, steep-sided...
Filter Total Items: 79
Examples of eruption response teams from the Alaska Volcano Observatory Examples of eruption response teams from the Alaska Volcano Observatory
During times of eruption response, volcano observatories need to organize themselves differently than during normal operations. The number of formal operational roles grows to ensure that critical responsibilities are covered, including management of all activities at the observatory as well as increased staffing to ensure proper surveillance of data and issuance of timely notices and...
Authors
Michelle L. Coombs, Kristi L. Wallace, Ronni Grapenthin, Jordan Edward Lubbers, Tom Murray
Mount Spurr Volcano Mount Spurr Volcano
No abstract available.
Authors
Kristi L. Wallace, Christopher F. Waythomas, Michelle L. Coombs, A.M. Nastan
Insights on arc magmatic systems drawn from natural melt inclusions and crystallization experiments at PH2O=800 MPa under oxidizing conditions Insights on arc magmatic systems drawn from natural melt inclusions and crystallization experiments at PH2O=800 MPa under oxidizing conditions
Whole rock compositions at Buldir Volcano, western Aleutian arc, record a strong, continuous trend of iron depletion with decreasing MgO, classically interpreted as a calc-alkaline liquid line of descent. In contrast, olivine-hosted melt inclusions have higher total iron (FeO*) than whole rocks and show little change in FeO* with decreasing MgO. To investigate this discrepancy and...
Authors
Janine L. Andrys, Elizabeth Cottrell, Katherine A. Kelley, Laura E. Waters, Michelle L. Coombs
Introduction to recommended capabilities and instrumentation for volcano monitoring in the United States Introduction to recommended capabilities and instrumentation for volcano monitoring in the United States
Authors
Ashton F. Flinders, Jacob B. Lowenstern, Michelle L. Coombs, Michael P. Poland
Recommended capabilities and instrumentation for volcano monitoring in the United States Recommended capabilities and instrumentation for volcano monitoring in the United States
The National Volcano Early Warning System (NVEWS) was authorized and partially funded by the U.S. Government in 2019. In response, the U.S. Geological Survey (USGS) Volcano Hazards Program asked its scientists to reflect on and summarize their views of best practices for volcano monitoring. The goal was to review and update the recommendations of a previous report (Moran and others, 2008...
From field station to forecast: Managing data at the Alaska Volcano Observatory From field station to forecast: Managing data at the Alaska Volcano Observatory
The Alaska Volcano Observatory (AVO) uses multidisciplinary data to monitor and study dozens of active and potentially active volcanoes. Here, we provide an overview of internally and externally generated data types, tools and resources used in their management, and challenges faced. Data sources include the following: (1) a multiparameter (seismic, infrasound, GNSS, web cameras) ground...
Authors
Michelle L. Coombs, Cheryl Cameron, Hannah R. Dietterich, Eleanor Boyce, Aaron Wech, Ronni Grapenthin, Kristi L. Wallace, Thomas Parker, Taryn Lopez, Scott Crass, David Fee, Matthew M. Haney, Dane M. Ketner, Matthew W. Loewen, John J. Lyons, Jenny Sha Nakai, John A. Power, Steven M Botnick, Israel Brewster, Max L. Enders, Dain Harmon, Peter J. Kelly, Michael J. Randall
Probabilistic source classification of large tephra producing eruptions using supervised machine learning: An example from the Alaska-Aleutian arc Probabilistic source classification of large tephra producing eruptions using supervised machine learning: An example from the Alaska-Aleutian arc
Alaska contains over 130 volcanoes and volcanic fields that have been active within the last 2 million years. Of these, roughly 90 have erupted during the Holocene, with many characterized by at least one large explosive eruption. These large tephra-producing eruptions (LTPEs) generate orders of magnitude more erupted material than a “typical” arc explosive eruption and distribute ash...
Authors
Jordan Edward Lubbers, Matthew W. Loewen, Kristi L. Wallace, Michelle L. Coombs, Jason A. Addison
Coordinating science during an eruption: Lessons from the 2020–2021 Kīlauea volcanic eruption Coordinating science during an eruption: Lessons from the 2020–2021 Kīlauea volcanic eruption
Data collected during well-observed eruptions can lead to dramatic increases in our understanding of volcanic processes. However, the necessary prioritization of public safety and hazard mitigation during a crisis means that scientific opportunities may be sacrificed. Thus, maximizing the scientific gains from eruptions requires improved planning and coordinating science activities among
Authors
Kari M. Cooper, Kyle R. Anderson, Kathy Cashman, Michelle L. Coombs, Hannah R. Dietterich, Tobias Fischer, Bruce F. Houghton, Ingrid A. Johanson, Kendra J. Lynn, Michael Manga, Christelle Wauthier
Eruption of compositionally heterogeneous andesites from a complex storage region during the 2006 eruption of Augustine Volcano Eruption of compositionally heterogeneous andesites from a complex storage region during the 2006 eruption of Augustine Volcano
Despite the common occurrence of heterogeneous andesitic eruptions, few studies have investigated the compositional effects on microlite crystallization and vesiculation in co-erupted natural samples. In 2006, Augustine Volcano erupted compositionally heterogeneous andesites that range from 56.4 to 63.3 wt% SiO2 and include two endmember lithologic groups: low-silica andesite (LSA) and...
Authors
Mary Catherine Benage, Heather M. Wright, Michelle L. Coombs
Generation of calc-alkaline magmas during crystallization at high oxygen fugacity: An experimental and petrologic study of tephras from Buldir Volcano, western Aleutian Arc, Alaska, USA Generation of calc-alkaline magmas during crystallization at high oxygen fugacity: An experimental and petrologic study of tephras from Buldir Volcano, western Aleutian Arc, Alaska, USA
Despite agreement that calc-alkaline volcanism occurs at subduction zones and is responsible for the genesis of continental landmasses, there is no consensus on the source of the Fe-depleted signature hallmark to calc-alkaline volcanism. In this study, we utilize mafic tephras collected from Buldir Volcano to address the genesis of strongly calc-alkaline volcanic rocks (those with a low...
Authors
Laura Waters, Elizabeth Cottrell, Michelle L. Coombs, Katherine A. Kelley
The eruptive history, magmatic evolution, and influence of glacial ice at long-lived Akutan volcano, eastern Aleutian Islands, Alaska, USA The eruptive history, magmatic evolution, and influence of glacial ice at long-lived Akutan volcano, eastern Aleutian Islands, Alaska, USA
New 40Ar/39Ar and whole-rock geochemical data are used to develop a detailed eruptive chronology for Akutan volcano, Akutan Island, Alaska, USA, in the eastern Aleutian island arc. Akutan Island (166°W, 54.1°N) is the site of long-lived volcanism and the entire island comprises volcanic rocks as old as 3.3 Ma. Our current study is on the 225 km2 western half of the island, where our...
Authors
Michelle L. Coombs, Brian Jicha
U.S. Geological Survey 2018 Kīlauea Volcano eruption response in Hawai'i—After-action review U.S. Geological Survey 2018 Kīlauea Volcano eruption response in Hawai'i—After-action review
The 2018 Kīlauea Volcano eruption lasted 107 days, and now ranks as the most destructive event at Kilauea since 1790, and as one of the most costly volcanic disasters in U.S. history. Multiple simultaneous hazard events unfolded, including sustained seismic activity leading to collapse at the summit of Halema'uma'u crater and severe damage to the HVO facility, with additional eruption of...
Authors
Dee M. Williams, Vic F. Avery, Michelle L. Coombs, Dale A. Cox, Lief R. Horwitz, Sara K. McBride, Ryan J. McClymont, Seth C. Moran