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
Filter Total Items: 79
Major-element, sulfur, and chlorine compositions of glasses from the submarine flank of Kilauea Volcano, Hawaii, Collected During 1998-2002 Japan Marine Science and Technology Center (JAMSTEC) Cruises Major-element, sulfur, and chlorine compositions of glasses from the submarine flank of Kilauea Volcano, Hawaii, Collected During 1998-2002 Japan Marine Science and Technology Center (JAMSTEC) Cruises
No abstract available.
Authors
Michelle L. Coombs, Thomas W. Sisson, Peter W. Lipman
Renewed unrest at Mount Spurr Volcano, Alaska Renewed unrest at Mount Spurr Volcano, Alaska
The Alaska Volcano Observatory (AVO),a cooperative program of the U.S. Geological Survey, the University of Alaska Fairbanks Geophysical Institute, and the Alaska Division of Geological and Geophysical Surveys, has detected unrest at Mount Spurr volcano, located about 125 km west of Anchorage, Alaska, at the northeast end of the Aleutian volcanic arc. This activity consists of increased...
Authors
John A. Power
Ultra-high chlorine in submarine Kı̄lauea glasses: Evidence for direct assimilation of brine by magma Ultra-high chlorine in submarine Kı̄lauea glasses: Evidence for direct assimilation of brine by magma
Basaltic glass grains from the submarine south flank of Kı̄lauea, Hawai′i, have Cl concentrations of 0.01–1.68 wt%, the latter being the highest Cl content yet recorded for a Hawaiian glass. The high-Cl glass grains are products of brine assimilation by tholeiite magma. The glasses are grains in a sandstone clast from bedded breccias draping the southwestern margin of Kı̄lauea’s...
Authors
Michelle L. Coombs, Thomas W. Sisson, Jun-Ichi Kimura
Reaction rim growth on olivine in silicic melts: Implications for magma mixing Reaction rim growth on olivine in silicic melts: Implications for magma mixing
Finely crystalline amphibole or pyroxene rims that form during reaction between silicic host melt and cognate olivine xenocrysts, newly introduced during magma mixing events, can provide information about the timing between mixing and volcanic eruptions. We investigated rim growth experimentally by placing forsteritic olivine in rhyolitic and rhyodacitic melts for times between 25 and...
Authors
Michelle L. Coombs, James E. Gardner
Growth and collapse of Waianae volcano, Hawaii, as revealed by exploration of its submarine flanks Growth and collapse of Waianae volcano, Hawaii, as revealed by exploration of its submarine flanks
Wai‘anae Volcano comprises the western half of O‘ahu Island, but until recently little was known about the submarine portion of this volcano. Seven new submersible dives, conducted in 2001 and 2002, and multibeam bathymetry offshore of Wai‘anae provide evidence pertaining to the overall growth of the volcano's edifice as well as the timing of collapses that formed the Wai‘anae slump...
Authors
Michelle L. Coombs, David A. Clague, Gregory F. Moore, Brian L. Cousens
Shallow-storage conditions for the rhyolite of the 1912 eruption at Novarupta, Alaska Shallow-storage conditions for the rhyolite of the 1912 eruption at Novarupta, Alaska
Recent studies have proposed contrasting models for the plumbing system that fed the 1912 eruption of Novarupta, Alaska. Here, we investigate the conditions under which the rhyolitic part of the erupted magma last resided in the crust prior to eruption. Geothermometry suggests that the rhyolite was held at ∼800-850 °C, and analyses of melt inclusions suggest that it was fluid saturated...
Authors
Michelle L. Coombs, James E. Gardner
Magma storage and mixing conditions for the 1953-1974 eruption of Southwest Trident volcano, Katmai National Park, Alaska Magma storage and mixing conditions for the 1953-1974 eruption of Southwest Trident volcano, Katmai National Park, Alaska
Between 1953 and 1974, approximately 0.5 km3 of andesite and dacite erupted from a new vent on the southwest flank of Trident volcano in Katmai National Park, Alaska, forming an edifice now known as Southwest (or New) Trident. Field, analytical, and experimental evidence shows that the eruption commenced soon after mixing of dacite and andesite magmas at shallow crustal levels. Four lava...
Authors
Michelle L. Coombs, John C. Eichelberger, Malcom J. Rutherford
Science and Products
Filter Total Items: 79
Major-element, sulfur, and chlorine compositions of glasses from the submarine flank of Kilauea Volcano, Hawaii, Collected During 1998-2002 Japan Marine Science and Technology Center (JAMSTEC) Cruises Major-element, sulfur, and chlorine compositions of glasses from the submarine flank of Kilauea Volcano, Hawaii, Collected During 1998-2002 Japan Marine Science and Technology Center (JAMSTEC) Cruises
No abstract available.
Authors
Michelle L. Coombs, Thomas W. Sisson, Peter W. Lipman
Renewed unrest at Mount Spurr Volcano, Alaska Renewed unrest at Mount Spurr Volcano, Alaska
The Alaska Volcano Observatory (AVO),a cooperative program of the U.S. Geological Survey, the University of Alaska Fairbanks Geophysical Institute, and the Alaska Division of Geological and Geophysical Surveys, has detected unrest at Mount Spurr volcano, located about 125 km west of Anchorage, Alaska, at the northeast end of the Aleutian volcanic arc. This activity consists of increased...
Authors
John A. Power
Ultra-high chlorine in submarine Kı̄lauea glasses: Evidence for direct assimilation of brine by magma Ultra-high chlorine in submarine Kı̄lauea glasses: Evidence for direct assimilation of brine by magma
Basaltic glass grains from the submarine south flank of Kı̄lauea, Hawai′i, have Cl concentrations of 0.01–1.68 wt%, the latter being the highest Cl content yet recorded for a Hawaiian glass. The high-Cl glass grains are products of brine assimilation by tholeiite magma. The glasses are grains in a sandstone clast from bedded breccias draping the southwestern margin of Kı̄lauea’s...
Authors
Michelle L. Coombs, Thomas W. Sisson, Jun-Ichi Kimura
Reaction rim growth on olivine in silicic melts: Implications for magma mixing Reaction rim growth on olivine in silicic melts: Implications for magma mixing
Finely crystalline amphibole or pyroxene rims that form during reaction between silicic host melt and cognate olivine xenocrysts, newly introduced during magma mixing events, can provide information about the timing between mixing and volcanic eruptions. We investigated rim growth experimentally by placing forsteritic olivine in rhyolitic and rhyodacitic melts for times between 25 and...
Authors
Michelle L. Coombs, James E. Gardner
Growth and collapse of Waianae volcano, Hawaii, as revealed by exploration of its submarine flanks Growth and collapse of Waianae volcano, Hawaii, as revealed by exploration of its submarine flanks
Wai‘anae Volcano comprises the western half of O‘ahu Island, but until recently little was known about the submarine portion of this volcano. Seven new submersible dives, conducted in 2001 and 2002, and multibeam bathymetry offshore of Wai‘anae provide evidence pertaining to the overall growth of the volcano's edifice as well as the timing of collapses that formed the Wai‘anae slump...
Authors
Michelle L. Coombs, David A. Clague, Gregory F. Moore, Brian L. Cousens
Shallow-storage conditions for the rhyolite of the 1912 eruption at Novarupta, Alaska Shallow-storage conditions for the rhyolite of the 1912 eruption at Novarupta, Alaska
Recent studies have proposed contrasting models for the plumbing system that fed the 1912 eruption of Novarupta, Alaska. Here, we investigate the conditions under which the rhyolitic part of the erupted magma last resided in the crust prior to eruption. Geothermometry suggests that the rhyolite was held at ∼800-850 °C, and analyses of melt inclusions suggest that it was fluid saturated...
Authors
Michelle L. Coombs, James E. Gardner
Magma storage and mixing conditions for the 1953-1974 eruption of Southwest Trident volcano, Katmai National Park, Alaska Magma storage and mixing conditions for the 1953-1974 eruption of Southwest Trident volcano, Katmai National Park, Alaska
Between 1953 and 1974, approximately 0.5 km3 of andesite and dacite erupted from a new vent on the southwest flank of Trident volcano in Katmai National Park, Alaska, forming an edifice now known as Southwest (or New) Trident. Field, analytical, and experimental evidence shows that the eruption commenced soon after mixing of dacite and andesite magmas at shallow crustal levels. Four lava...
Authors
Michelle L. Coombs, John C. Eichelberger, Malcom J. Rutherford