Michelle L. Coombs, Ph.D.
Michelle Coombs is a Research Geologist with the U.S. Geological Survey Volcanic Science Center. She served as Scientist-in-Charge of the Alaska Volcano Observatory from 2016-2023. In this position, Dr. Coombs leads eruption responses, oversees expansion and modernization of volcano monitoring techniques, and guides applied and fundamental research on a host of problems related to volcanology.
Professional Experience
2016–2023: Scientist-in-Charge, Alaska Volcano Observatory, Volcano Science Center, U.S. Geological Survey, Anchorage, AK
2004–Present: Research Geologist, Alaska Volcano Observatory
2001–2004: Research Geologist, Volcano Hazards Team, U.S. Geological Survey, Menlo Park CA
OTHER PROFESSIONAL ACTIVITIES
Affiliate faculty, University of Alaska Fairbanks
CONVERSE Steering Committee member, 2020–present
Member of AGU student awards committee, 2011–2015
Associate Editor, Bulletin of Volcanology, 2013–2016
Editorial board, Journal of Volcanology and Geothermal Research, 2007–2018
Co-editor for 28-chapter USGS Professional Paper 1769, The 2006 eruption of Augustine Volcano, Alaska, 2010
Co-editor for Journal of Volcanology and Geothermal Research special issue on Growth and collapse of Hawaiian volcanoes, 2006
Education and Certifications
Williams College, BA Geology, 1994
University of Alaska Fairbanks, PhD Geology, 2001
Affiliations and Memberships*
American Geophysical Union, 1996–present
Geological Society of America, 2001–present (elected Fellow in 2015)
International Assoc. of Volcanology and Chemistry of the Earth’s Interior, 1999–present
Science and Products
Filter Total Items: 75
On the eruption age and provenance of the Old Crow tephra
Tephrochronology is used to correlate and reconstruct geographically disparate sedimentary records of changing environment, climate, and landscape throughout geologic time. Single tephra layers represent isochronous markers across broad regions, thus accurate and precise radiometric constraints on the timing of eruption are critical to their utility. The Old Crow tephra is found throughout eastern
Authors
Seth D. Burgess, Matthew Coble, Jorge A. Vazquez, Michelle L. Coombs, Kristi L. Wallace
The 2018 rift eruption and summit collapse of Kilauea Volcano
In 2018, Kīlauea Volcano experienced its largest lower East Rift Zone (LERZ) eruption and caldera collapse in at least 200 years. After collapse of the Pu'u 'Ō'ō vent on 30 April, magma propagated downrift. Eruptive fissures opened in the LERZ on 3 May, eventually extending ~6.8 km. A 4 May earthquake (M6.9) produced ~5 m of fault slip. Lava erupted at rates exceeding 100 m3/s, eventually coveri
Authors
Christina A. Neal, Steven Brantley, Loren Antolik, Janet Babb, Matthew K. Burgess, Michael Cappos, Jefferson Chang, Sarah Conway, Liliana G. Desmither, Peter Dotray, Tamar Elias, Pauline Fukunaga, Steven Fuke, Ingrid A. Johanson, Kevan Kamibayashi, James P. Kauahikaua, R. Lopaka Lee, S. Pekalib, Asta Miklius, Brian Shiro, Don Swanson, Patricia A. Nadeau, Michael H. Zoeller, P. Okubo, Carolyn Parcheta, Matthew R. Patrick, William Tollett, Frank A. Trusdell, Edward F. Younger, Emily K. Montgomery-Brown, Kyle R. Anderson, Michael P. Poland, Jessica L. Ball, Joseph A. Bard, Michelle L. Coombs, Hannah R. Dietterich, Christoph Kern, Weston Thelen, Peter Cervelli, Tim R. Orr, Bruce F. Houghton, Cheryl Gansecki, Richard Hazlett, Paul Lundgren, Angela K. Diefenbach, Allan Lerner, Greg Waite, Peter J. Kelly, Laura E. Clor, Cynthia Werner, Katherine Mulliken, Gary B. Fisher, David Damby
Short-term forecasting and detection of explosions during the 2016–2017 eruption of Bogoslof volcano, Alaska
We describe a multidisciplinary approach to forecast, rapidly detect, and characterize explosive events during the 2016–2017 eruption of Bogoslof volcano, a back-arc shallow submarine volcano in Alaska’s Aleutian arc. The eruptive sequence began in December 2016 and included about 70 discrete explosive events. Because the volcano has no local monitoring stations, we used distant stations on the ne
Authors
Michelle L. Coombs, Aaron Wech, Matthew M. Haney, John J. Lyons, David J. Schneider, Hans Schwaiger, Kristi L. Wallace, David Fee, Jeffrey T. Freymueller, Janet Schaefer, Gabrielle Tepp
Alaska Volcano Observatory alert and forecasting timeliness: 1989–2017
The Alaska Volcano Observatory (AVO) monitors volcanoes in Alaska and issues notifications and warnings of volcanic unrest and eruption. We evaluate the timeliness and accuracy of eruption forecasts for 53 eruptions at 20 volcanoes, beginning with Mount Redoubt's 1989–1990 eruption. Successful forecasts are defined as those where AVO issued a formal warning before eruption onset. These warning not
Authors
Cheryl Cameron, Stephanie Prejean, Michelle L. Coombs, Kristi L. Wallace, John Power, Diana C. Roman
Postglacial eruptive history and geochemistry of Semisopochnoi volcano, western Aleutian Islands, Alaska
Semisopochnoi Island, located in the Rat Islands group of the western Aleutian Islands and Aleutian volcanic arc, is a roughly circular island composed of scattered volcanic vents, the prominent caldera of Semisopochnoi volcano, and older, ancestral volcanic rocks. The oldest rocks on the island are gently radially dipping lavas that are the remnants of a shield volcano and of Ragged Top, which is
Authors
Michelle L. Coombs, Jessica F. Larsen, Christina A. Neal
Amphibole reaction rims as a record of pre-eruptive magmatic heating: An experimental approach
Magmatic minerals record the pre-eruptive timescales of magma ascent and mixing in crustal reservoirs and conduits. Investigations of the mineral records of magmatic processes are fundamental to our understanding of what controls eruption style, as ascent rates and magma mixing processes are well known to control and/or trigger potentially hazardous explosive eruptions. Thus, amphibole reaction ri
Authors
S. H. De Angelis, J. Larsen, Michelle L. Coombs, A. Dunn, Leslie A. Hayden
Significance of a near-source tephra-stratigraphic sequence to the eruptive history of Hayes Volcano, south-central Alaska
Bluffs along the Hayes River valley, 31 km northeast and 40 km downstream from Hayes Volcano, reveal volcanic deposits that shed new light on its eruptive history. Three thick (>10 cm) and five thin (<10 cm) tephra-fall deposits are dacitic in whole rock composition and contain high proportions of amphibole to pyroxene and minor biotite and broadly correlate to Hayes tephra set H defined by earlie
Authors
Kristi L. Wallace, Michelle L. Coombs, Leslie A. Hayden, Christopher F. Waythomas
Cogenetic late Pleistocene rhyolite and cumulate diorites from Augustine Volcano revealed by SIMS 238U-230Th dating of zircon, and implications for silicic magma generation by extraction from mush
Augustine Volcano, a frequently active andesitic island stratocone, erupted a late Pleistocene rhyolite pumice fall that is temporally linked through zircon geochronology to cumulate dioritic blocks brought to the surface in Augustine's 2006 eruption. Zircon from the rhyolite yield a 238U-230Th age of ∼25 ka for their unpolished rims, and their interiors yield a bimodal age populations at ∼26 ka a
Authors
Michelle L. Coombs, Jorge A. Vazquez
Constructing a reference tephrochronology for Augustine Volcano, Alaska
Augustine Volcano is the most historically active volcano in Alaska's populous Cook Inlet region. Past on-island work on pre-historic tephra deposits mainly focused on using tephra layers as markers to help distinguish among prevalent debris-avalanche deposits on the island (Waitt and Beget, 2009, USGS Prof Paper 1762), or as source material for petrogenetic studies. No comprehensive reference stu
Authors
Kristi L. Wallace, Michelle L. Coombs
Volcano–ice interactions precursory to the 2009 eruption of Redoubt Volcano, Alaska
In late summer of 2008, after nearly 20 years of quiescence, Redoubt Volcano began to show signs of abnormal heat flow in its summit crater. In the months that followed, the excess heat triggered melting and ablation of Redoubt's glaciers, beginning at the summit and propagating to lower elevations as the unrest accelerated. A variety of morphological changes were observed, including the creation
Authors
Heather A. Bleick, Michelle L. Coombs, Peter F. Cervelli, Katharine F. Bull, Rick Wessels
High-resolution satellite and airborne thermal infrared imaging of precursory unrest and 2009 eruption of Redoubt Volcano, Alaska
A combination of satellite and airborne high-resolution visible and thermal infrared (TIR) image data detected and measured changes at Redoubt Volcano during the 2008–2009 unrest and eruption. The TIR sensors detected persistent elevated temperatures at summit ice-melt holes as seismicity and gas emissions increased in late 2008 to March 2009. A phreatic explosion on 15 March was followed by more
Authors
Rick L. Wessels, R. Greg Vaughan, Matthew R. Patrick, Michelle L. Coombs
Andesites of the 2009 eruption of Redoubt Volcano, Alaska
Crystal-rich andesites that erupted from Redoubt Volcano in 2009 range from 57.5 to 62.5 wt.% SiO2 and have phenocryst and phenocryst-melt relations consistent with staging in the upper crust. Early explosive products are low-silica andesites (LSA, < 58 wt.% SiO2) that ascended from deeper crustal levels during or before the 6 months of precursory activity, but a broad subsequent succession to mor
Authors
Michelle L. Coombs, Thomas W. Sisson, Heather A. Bleick, Sarah M. Henton, Christopher J. Nye, Allison Payne, Cheryl E. Cameron, Jessica F. Larsen, Kristi L. Wallace, Katharine F. Bull
Science and Products
Filter Total Items: 75
On the eruption age and provenance of the Old Crow tephra
Tephrochronology is used to correlate and reconstruct geographically disparate sedimentary records of changing environment, climate, and landscape throughout geologic time. Single tephra layers represent isochronous markers across broad regions, thus accurate and precise radiometric constraints on the timing of eruption are critical to their utility. The Old Crow tephra is found throughout eastern
Authors
Seth D. Burgess, Matthew Coble, Jorge A. Vazquez, Michelle L. Coombs, Kristi L. Wallace
The 2018 rift eruption and summit collapse of Kilauea Volcano
In 2018, Kīlauea Volcano experienced its largest lower East Rift Zone (LERZ) eruption and caldera collapse in at least 200 years. After collapse of the Pu'u 'Ō'ō vent on 30 April, magma propagated downrift. Eruptive fissures opened in the LERZ on 3 May, eventually extending ~6.8 km. A 4 May earthquake (M6.9) produced ~5 m of fault slip. Lava erupted at rates exceeding 100 m3/s, eventually coveri
Authors
Christina A. Neal, Steven Brantley, Loren Antolik, Janet Babb, Matthew K. Burgess, Michael Cappos, Jefferson Chang, Sarah Conway, Liliana G. Desmither, Peter Dotray, Tamar Elias, Pauline Fukunaga, Steven Fuke, Ingrid A. Johanson, Kevan Kamibayashi, James P. Kauahikaua, R. Lopaka Lee, S. Pekalib, Asta Miklius, Brian Shiro, Don Swanson, Patricia A. Nadeau, Michael H. Zoeller, P. Okubo, Carolyn Parcheta, Matthew R. Patrick, William Tollett, Frank A. Trusdell, Edward F. Younger, Emily K. Montgomery-Brown, Kyle R. Anderson, Michael P. Poland, Jessica L. Ball, Joseph A. Bard, Michelle L. Coombs, Hannah R. Dietterich, Christoph Kern, Weston Thelen, Peter Cervelli, Tim R. Orr, Bruce F. Houghton, Cheryl Gansecki, Richard Hazlett, Paul Lundgren, Angela K. Diefenbach, Allan Lerner, Greg Waite, Peter J. Kelly, Laura E. Clor, Cynthia Werner, Katherine Mulliken, Gary B. Fisher, David Damby
Short-term forecasting and detection of explosions during the 2016–2017 eruption of Bogoslof volcano, Alaska
We describe a multidisciplinary approach to forecast, rapidly detect, and characterize explosive events during the 2016–2017 eruption of Bogoslof volcano, a back-arc shallow submarine volcano in Alaska’s Aleutian arc. The eruptive sequence began in December 2016 and included about 70 discrete explosive events. Because the volcano has no local monitoring stations, we used distant stations on the ne
Authors
Michelle L. Coombs, Aaron Wech, Matthew M. Haney, John J. Lyons, David J. Schneider, Hans Schwaiger, Kristi L. Wallace, David Fee, Jeffrey T. Freymueller, Janet Schaefer, Gabrielle Tepp
Alaska Volcano Observatory alert and forecasting timeliness: 1989–2017
The Alaska Volcano Observatory (AVO) monitors volcanoes in Alaska and issues notifications and warnings of volcanic unrest and eruption. We evaluate the timeliness and accuracy of eruption forecasts for 53 eruptions at 20 volcanoes, beginning with Mount Redoubt's 1989–1990 eruption. Successful forecasts are defined as those where AVO issued a formal warning before eruption onset. These warning not
Authors
Cheryl Cameron, Stephanie Prejean, Michelle L. Coombs, Kristi L. Wallace, John Power, Diana C. Roman
Postglacial eruptive history and geochemistry of Semisopochnoi volcano, western Aleutian Islands, Alaska
Semisopochnoi Island, located in the Rat Islands group of the western Aleutian Islands and Aleutian volcanic arc, is a roughly circular island composed of scattered volcanic vents, the prominent caldera of Semisopochnoi volcano, and older, ancestral volcanic rocks. The oldest rocks on the island are gently radially dipping lavas that are the remnants of a shield volcano and of Ragged Top, which is
Authors
Michelle L. Coombs, Jessica F. Larsen, Christina A. Neal
Amphibole reaction rims as a record of pre-eruptive magmatic heating: An experimental approach
Magmatic minerals record the pre-eruptive timescales of magma ascent and mixing in crustal reservoirs and conduits. Investigations of the mineral records of magmatic processes are fundamental to our understanding of what controls eruption style, as ascent rates and magma mixing processes are well known to control and/or trigger potentially hazardous explosive eruptions. Thus, amphibole reaction ri
Authors
S. H. De Angelis, J. Larsen, Michelle L. Coombs, A. Dunn, Leslie A. Hayden
Significance of a near-source tephra-stratigraphic sequence to the eruptive history of Hayes Volcano, south-central Alaska
Bluffs along the Hayes River valley, 31 km northeast and 40 km downstream from Hayes Volcano, reveal volcanic deposits that shed new light on its eruptive history. Three thick (>10 cm) and five thin (<10 cm) tephra-fall deposits are dacitic in whole rock composition and contain high proportions of amphibole to pyroxene and minor biotite and broadly correlate to Hayes tephra set H defined by earlie
Authors
Kristi L. Wallace, Michelle L. Coombs, Leslie A. Hayden, Christopher F. Waythomas
Cogenetic late Pleistocene rhyolite and cumulate diorites from Augustine Volcano revealed by SIMS 238U-230Th dating of zircon, and implications for silicic magma generation by extraction from mush
Augustine Volcano, a frequently active andesitic island stratocone, erupted a late Pleistocene rhyolite pumice fall that is temporally linked through zircon geochronology to cumulate dioritic blocks brought to the surface in Augustine's 2006 eruption. Zircon from the rhyolite yield a 238U-230Th age of ∼25 ka for their unpolished rims, and their interiors yield a bimodal age populations at ∼26 ka a
Authors
Michelle L. Coombs, Jorge A. Vazquez
Constructing a reference tephrochronology for Augustine Volcano, Alaska
Augustine Volcano is the most historically active volcano in Alaska's populous Cook Inlet region. Past on-island work on pre-historic tephra deposits mainly focused on using tephra layers as markers to help distinguish among prevalent debris-avalanche deposits on the island (Waitt and Beget, 2009, USGS Prof Paper 1762), or as source material for petrogenetic studies. No comprehensive reference stu
Authors
Kristi L. Wallace, Michelle L. Coombs
Volcano–ice interactions precursory to the 2009 eruption of Redoubt Volcano, Alaska
In late summer of 2008, after nearly 20 years of quiescence, Redoubt Volcano began to show signs of abnormal heat flow in its summit crater. In the months that followed, the excess heat triggered melting and ablation of Redoubt's glaciers, beginning at the summit and propagating to lower elevations as the unrest accelerated. A variety of morphological changes were observed, including the creation
Authors
Heather A. Bleick, Michelle L. Coombs, Peter F. Cervelli, Katharine F. Bull, Rick Wessels
High-resolution satellite and airborne thermal infrared imaging of precursory unrest and 2009 eruption of Redoubt Volcano, Alaska
A combination of satellite and airborne high-resolution visible and thermal infrared (TIR) image data detected and measured changes at Redoubt Volcano during the 2008–2009 unrest and eruption. The TIR sensors detected persistent elevated temperatures at summit ice-melt holes as seismicity and gas emissions increased in late 2008 to March 2009. A phreatic explosion on 15 March was followed by more
Authors
Rick L. Wessels, R. Greg Vaughan, Matthew R. Patrick, Michelle L. Coombs
Andesites of the 2009 eruption of Redoubt Volcano, Alaska
Crystal-rich andesites that erupted from Redoubt Volcano in 2009 range from 57.5 to 62.5 wt.% SiO2 and have phenocryst and phenocryst-melt relations consistent with staging in the upper crust. Early explosive products are low-silica andesites (LSA, < 58 wt.% SiO2) that ascended from deeper crustal levels during or before the 6 months of precursory activity, but a broad subsequent succession to mor
Authors
Michelle L. Coombs, Thomas W. Sisson, Heather A. Bleick, Sarah M. Henton, Christopher J. Nye, Allison Payne, Cheryl E. Cameron, Jessica F. Larsen, Kristi L. Wallace, Katharine F. Bull
*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