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Alexandra Iezzi, Ph.D.

My research focuses on using infrasound and seismic data to study and improve monitoring of volcanic events in the Cascades. In particular, I focus on lahar/debris flow research and the development of detection, localization, and characterization algorithms for these types of events. 

Professional Experience

  • 2022 - present: Research Geophysicist, Volcano Science Center, Cascades Volcano Observatory

  • 2020 - 2022: NSF Earth Sciences Postdoctoral Fellow, University of California Santa Barbara

  • 2015 - 2020: Graduate Research Assistant, Geophysical Institute, Alaska Volcano Observatory, University of Alaska Fairbanks

  • Summer 2019: Graduate Research Assistant, Los Alamos National Laboratory 

  • Summer 2014 & 2015: Physical Science Technician (180-day appointment), Volcano Science Center, Alaska Volcano Observatory

  • Winter 2014: Research Assistant (volunteer), Volcano Science Center, Cascades Volcano Observatory 

  • 2013 - 2015: Fluvial Studies Research Assistant, Connecticut College

Education and Certifications

  • 2020 - Ph.D. in Geophysics, University of Alaska Fairbanks

  • 2015 - B.A. in Geophysics (self-designed) with minors in Mathematics and Physics, Connecticut College

Science and Products

Infrasound Propagation Modeling Output for the 1992 eruption of Mount Spurr Infrasound Propagation Modeling Output for the 1992 eruption of Mount Spurr

Data release for the output of infrasound propagation modeling for the August 18th, 1992 eruption of Mount Spurr.
By
Volcano Science Center

Reports of Hearing and Not Hearing the 1992 eruption of Mount Spurr Reports of Hearing and Not Hearing the 1992 eruption of Mount Spurr

Observations of locations where the August 18th, 1992 eruption of Mount Spurr was heard and not heard around Alaska.
By
Volcano Science Center

Swath laser, laser rangefinder, and high-precision analog laser data from gate release and natural release experiments conducted in April 2024 and October 2022, respectively, at the USGS debris-flow flume, HJ Andrews Experimental Forest, Blue River, Orego Swath laser, laser rangefinder, and high-precision analog laser data from gate release and natural release experiments conducted in April 2024 and October 2022, respectively, at the USGS debris-flow flume, HJ Andrews Experimental Forest, Blue River, Orego

The swath laser was tested at the large-scale experimental USGS debris flow flume facility as a potential tool for mass movement detection. The tests were conducted during gate release experiments, where a large volume of sediment was released from a hopper; and during natural release experiments, where a sediment prism was watered until wide-spread Coulomb failure occurred. During the...
By
Volcano Science Center

Laser Rangefinder Data for Surficial Mass Movements in the Cascades Laser Rangefinder Data for Surficial Mass Movements in the Cascades

A laser rangefinder was used to record surficial mass movements at Cascades volcanoes and an experimental debris flow flume. Mass movements such as large lahars and smaller seasonal debris flows can occur at volcanoes in the Cascades. A combination of seismic, infrasound, tripwires, and webcams can be used to detect and characterize these flows. A laser rangefinder can be placed on the...
By
Volcano Science Center
the directions of infrasound from stations at Biscuit Basin and Geyser Hill converge on Giant Geyser
Backazimuth map showing infrasound directions that converge on Giant Geyser, Yellowstone National Park, when it erupted on September 10, 2026
Backazimuth map showing infrasound directions that converge on Giant Geyser, Yellowstone National Park, when it erupted on September 10, 2026
the directions of infrasound from stations at Biscuit Basin and Geyser Hill converge on Giant Geyser

Backazimuth map showing infrasound directions that converge on Giant Geyser, Yellowstone National Park, when it erupted on September 10, 2026

Backazimuth map showing infrasound directions that converge on Giant Geyser, Yellowstone National Park, when it erupted on September 10, 2026

Acoustic signals recorded at infrasound arrays (red inverted triangles) YBB (in Biscuit Basin) and YGH (near Geyser Hill), in Upper Geyser Basin, can be used to determine the direction from which low-frequency acoustic signals originated, also called the backazimuth.  This example is from 9:14 p.m.

By
Volcano Science Center, Yellowstone Volcano Observatory, Yellowstone
the directions of infrasound from stations at Biscuit Basin and Geyser Hill converge on Giant Geyser

Backazimuth map showing infrasound directions that converge on Giant Geyser, Yellowstone National Park, when it erupted on September 10, 2026

Backazimuth map showing infrasound directions that converge on Giant Geyser, Yellowstone National Park, when it erupted on September 10, 2026

Acoustic signals recorded at infrasound arrays (red inverted triangles) YBB (in Biscuit Basin) and YGH (near Geyser Hill), in Upper Geyser Basin, can be used to determine the direction from which low-frequency acoustic signals originated, also called the backazimuth.  This example is from 9:14 p.m.

By
Volcano Science Center, Yellowstone Volcano Observatory, Yellowstone
Plot showing acoustic signals over time Plot showing acoustic signals over time
May 3, 2025, bolide acoustic signal recorded by infrasound station in Yellowstone National Park
Plot showing acoustic signals over time

May 3, 2025, bolide acoustic signal recorded by infrasound station in Yellowstone National Park

May 3, 2025, bolide acoustic signal recorded by infrasound station in Yellowstone National Park

This audio clip is the infrasound recorded during 1 minute on May 3, 2025, at 9:33 p.m.

By
Hawaiian Volcano Observatory, Yellowstone Volcano Observatory
Plot showing acoustic signals over time

May 3, 2025, bolide acoustic signal recorded by infrasound station in Yellowstone National Park

May 3, 2025, bolide acoustic signal recorded by infrasound station in Yellowstone National Park

This audio clip is the infrasound recorded during 1 minute on May 3, 2025, at 9:33 p.m.

By
Hawaiian Volcano Observatory, Yellowstone Volcano Observatory
Seismic and infrasound data for the April 15, 2024, hydrothermal explosion on Porcelain Terrace at Norris Geyser Basin
Seismic and infrasound data for the April 15, 2024, hydrothermal explosion on Porcelain Terrace at Norris Geyser Basin
Seismic and infrasound data for the April 15, 2024, hydrothermal explosion on Porcelain Terrace at Norris Geyser Basin
Seismic and infrasound data for the April 15, 2024, hydrothermal explosion on Porcelain Terrace at Norris Geyser Basin

Seismic and infrasound data for the April 15, 2024, hydrothermal explosion on Porcelain Terrace at Norris Geyser Basin

Seismic and infrasound data for the April 15, 2024, hydrothermal explosion on Porcelain Terrace at Norris Geyser Basin

Seismic and infrasound data for the April 15, 2024, hydrothermal explosion on Porcelain Terrace at Norris Geyser Basin.  Top plot is seismic data from the YNM station, located at the Norris Geyser Basin Museum.  Middle plot is seismic data from station YNB, in the Ragged Hills of Norris Geyser Basin. Bottom plot is infrasound data from station YNB.&nb

By
Volcano Science Center, Yellowstone Volcano Observatory, Yellowstone
Seismic and infrasound data for the April 15, 2024, hydrothermal explosion on Porcelain Terrace at Norris Geyser Basin

Seismic and infrasound data for the April 15, 2024, hydrothermal explosion on Porcelain Terrace at Norris Geyser Basin

Seismic and infrasound data for the April 15, 2024, hydrothermal explosion on Porcelain Terrace at Norris Geyser Basin

Seismic and infrasound data for the April 15, 2024, hydrothermal explosion on Porcelain Terrace at Norris Geyser Basin.  Top plot is seismic data from the YNM station, located at the Norris Geyser Basin Museum.  Middle plot is seismic data from station YNB, in the Ragged Hills of Norris Geyser Basin. Bottom plot is infrasound data from station YNB.&nb

By
Volcano Science Center, Yellowstone Volcano Observatory, Yellowstone
Filter Total Items: 28

Seismoacoustic analysis of possible vent-drying sequence during phreatomagmatic activity on 13 July 2021 at Semisopochnoi Island, Alaska Seismoacoustic analysis of possible vent-drying sequence during phreatomagmatic activity on 13 July 2021 at Semisopochnoi Island, Alaska

Pulse-like infrasound accompanying volcanic phenomena sometimes suggests interaction with water at the crater. We focus on pulse-like infrasound observed at Semisopochnoi Island in the Aleutian Arc, Alaska, during the phreatomagmatic activity on 13 July 2021. Overflight observations confirmed a small, ephemeral water lake on the crater floor in June 2021. We examined temporal variations...
Authors
Dan Muramatsu, John J. Lyons, Hannah R. Dietterich, Mie Ichihara, Alexandra M. Iezzi
By
Volcano Hazards Program, Volcano Science Center

Mount Spurr volcano, August 18, 1992: The eruption heard around Alaska Mount Spurr volcano, August 18, 1992: The eruption heard around Alaska

The August 18, 1992, eruption of Mount Spurr volcano, Alaska, produced an impressive Vulcanian to Subplinian eruption column reaching up to 40 km above sea level that blanketed the nearby city of Anchorage with ash. At the time of the eruption, the Alaska Volcano Observatory received reports of audible sound hundreds of kilometers from the source from a variety of azimuths from the...
Authors
Alexandra M. Iezzi, John Power
By
Volcano Hazards Program, Volcano Science Center

The morphological response to the 13 May 2022 major explosive event at Stromboli volcano, Italy, characterised by high-resolution UAS surveys The morphological response to the 13 May 2022 major explosive event at Stromboli volcano, Italy, characterised by high-resolution UAS surveys

Since 2019, the frequency of major explosive eruptions at Stromboli volcano (Italy) has increased, heightening the exposure of population and scientists to the hazards posed by ejecta. Morphological changes can directly alter the hazard potential associated with these phenomena. Here, we present a quantitative morphological analysis of changes of the crater terrace area linked to the 13...
Authors
Markus Schmid, Ulrich Kueppers, Tullio Ricci, Riccardo Civico, Valeria Cigala, David Fee, Julia E. Gestrich, Alexandra M. Iezzi, Corrado Cimarelli, Caron E.J. Vossen, Richard Michael Buzard, Maurizio Ripepe, Giorgio Lacanna, Donald B. Dingwell
By
Volcano Hazards Program, Volcano Science Center

The first instrumentally detected hydrothermal explosion in Yellowstone National Park The first instrumentally detected hydrothermal explosion in Yellowstone National Park

Hydrothermal explosions are one of the geological hazards most likely to impact people in Yellowstone National Park, but their frequency is poorly known. Infrasound and seismic sensors identified an explosion in Norris Geyser Basin on 15 April 2024, at 14:56 MDT (20:56 UTC)—the first instrumentally detected hydrothermal explosion in the Yellowstone region. The event affected an area tens...
Authors
Michael Poland, Alexandra M. Iezzi, Jamie Farrell, R. Greg Vaughan
By
Natural Hazards Mission Area, Volcano Hazards Program, Astrogeology Science Center, Volcano Science Center, Yellowstone Volcano Observatory

Infrasonic directivity of monopole, dipole, and bipole ground-surface reflected sources Infrasonic directivity of monopole, dipole, and bipole ground-surface reflected sources

Infrasound (acoustic waves below 20 Hz) can be used to detect, locate and quantify activity in the atmosphere such as volcanic eruptions and anthropogenic explosions. Attempts to quantify volcanic eruption parameters such as exit velocity, plume height and mass flow rate using infrasound data depend strongly on assumptions of the acoustic source type. Infrasonic sources may produce...
Authors
Alexandra M. Iezzi, Robin S. Matoza, Emma V. Opper, Keehoon Kim
By
Volcano Hazards Program, Volcano Science Center

Utility of a swath laser rangefinder for characterizing mass movement flow depth and landslide initiation Utility of a swath laser rangefinder for characterizing mass movement flow depth and landslide initiation

Mass movements such as debris flows and landslides are some of the deadliest and most destructive natural hazards occurring mostly in alpine and volcanic settings. With ever-growing populations located downslope from known debris flow channels, early warning systems can help prevent loss of life. Geophysical and technological advances have improved monitoring and detection capabilities...
Authors
Maciej K. Obryk, Emily Christina Bedinger, Alexandra M. Iezzi, Emily H Bryant, Kate E. Allstadt, David L. George, Benjamin B. Mirus
By
Natural Hazards Mission Area, Volcano Hazards Program, Geologic Hazards Science Center, Volcano Science Center

Infrasound for volcano monitoring Infrasound for volcano monitoring

20 hertz [Hz]), but the most energetic band is typically in the infrasound from 0.5 to 20 Hz. Studies of volcanic infrasound and the deployment of infrasound for volcano monitoring have increased rapidly in the past two decades as sensors have improved and as analytical tools have become more widely available. Improved sensors and tools have led to a growing diversity of eruptive...
Authors
John J. Lyons, David Fee, Weston A. Thelen, Alexandra M. Iezzi, Aaron G. Wech
By
Volcano Hazards Program, Volcano Science Center

Monitoring lahars Monitoring lahars

Authors
Weston A. Thelen, John J. Lyons, Alexandra M. Iezzi, Seth C. Moran
By
Volcano Hazards Program, Volcano Science Center

Debris-flow monitoring on volcanoes via a novel usage of a laser rangefinder Debris-flow monitoring on volcanoes via a novel usage of a laser rangefinder

Mount Rainier has had at least 11 large lahars over the last 6,000 years, including one occurring without evidence of eruptive activity. This prompted the creation of a lahar detection system that uses a combination of seismic, infrasound, and tripwires. We test a laser rangefinder placed on a river channel bank for detecting and confirming mass movements flowing past a station as an...
Authors
Alexandra M. Iezzi, Emily H Bryant, Weston Thelen, Craig Gabrielson, Seth C. Moran, Matthew R. Patrick, Edward F. Younger, Maciej K. Obryk
By
Volcano Hazards Program, Volcano Science Center

Recent expansion of the Cascades Volcano Observatory geophysical network at Mount Rainier for improved volcano and lahar monitoring Recent expansion of the Cascades Volcano Observatory geophysical network at Mount Rainier for improved volcano and lahar monitoring

The U.S. Geological Survey Cascades Volcano Observatory (CVO) recently expanded its continuous geophysical monitoring at Mount Rainier, an active stratovolcano in Washington state. CVO monitors volcanoes in Oregon, Washington, and Idaho to characterize volcanic systems and detect unrest. Mount Rainier has a history of large lahar occurrences in the Holocene, including at least one that...
Authors
Rebecca Kramer, Weston Thelen, Alexandra M. Iezzi, Seth C. Moran, Benjamin Pauk
By
Volcano Hazards Program, Volcano Science Center

Lessons learned from the 2022 CONVERSE Monogenetic Volcanism Response Scenario exercise Lessons learned from the 2022 CONVERSE Monogenetic Volcanism Response Scenario exercise

When volcanic unrest occurs, the scientific community can advance fundamental understanding of volcanic systems, but only with coordination before, during, and after the event across academic and governmental agencies. To develop a coordinated response plan, the Community Network for Volcanic Eruption Response (CONVERSE) orchestrated a scenario exercise centered around a hypothetical...
Authors
Yolanda C Lin, Einat Lev, Ria Mukerji, Tobias P. Fischer, Charles B. Connor, Wendy K. Stovall, Michael Poland, Alexandra M. Iezzi, Christelle Wauthier, Judit Gonzalez-Santana, Heather M. Wright, Samantha Wolf, Tobi Kasali
By
Volcano Hazards Program, Volcano Science Center

Introduction to the special section on seismoacoustics and seismoacoustic data fusion Introduction to the special section on seismoacoustics and seismoacoustic data fusion

A variety of geophysical hazards (e.g., volcanic activity, earthquakes, mass movements, marine storms, bolides) and anthropogenic sources (e.g., chemical and nuclear explosions, mining blasts, rocket launches) can release energy as mechanical waves in the ground, ocean, and atmosphere (Arrowsmith et al., 2010; Campus and Christie, 2009). Due to the mechanical coupling between a planetary...
Authors
Fransiska K. Dannemann Dugick, Jordan W. Bishop, Leo Martire, Alexandra M. Iezzi, Jelle D. Assink, Quentin Brissaud, Stephen Arrowsmith
By
Volcano Hazards Program, Volcano Science Center

Non-USGS Publications**

Iezzi, A.M., Matoza R.S., Bishop, J.W., Bhetanabhotla, S., and Fee, D. (2022), Narrow-Band Least-Squares Infrasound Array Processing, Seismological Research Letters: Electronic Seismologist, 93, 5, https://doi.org/10.1785/0220220042
Watson, L.M., Iezzi, A.M., Toney, L., Maher, S.P., Fee, D., McKee, K., Ortiz, H.D., Matoza, R.S., Anderson, J.F., Witsil, A.J.C., Gestrich, J.E., Bishop, J.W., and Johnson, J.B. (2022), Volcano Infrasound: Progress and Future Directions, Bulletin of Volcanology, 84, 44, https://doi.org/10.1007/s00445-022-01544-w
Blom, P.S., Iezzi, A.M., and Euler, G. (2020), Seismoacoustic analysis of underground explosions using the Rayleigh integral, Geophysical Journal International, 223, 1069–1085. https://doi.org/10.1093/gji/ggaa363
Iezzi, A.M., Fee, D., Kim, K., Jolly, A.D., and Matoza, R.S. (2019), Three-Dimensional Acoustic Multipole Waveform Inversion at Yasur Volcano, Vanuatu, Journal of Geophysical Research: Solid Earth, 124, 8679-8703. https://doi.org/10.1029/2018JB017073
Diaz-Moreno, A., Iezzi, A.M., Lamb, O.D., Fee, D., Kim, K., Zuccarello, L., and De Angelis, S. (2019), Volume Flow Rate Estimation for Small Explosions at Mt. Etna, Italy, From Acoustic Waveform Inversion, Geophysical Research Letters, 46, 11071-11079. https://doi.org/10.1029/2019GL084598
Jolly, A.D., Matoza, R.S., Fee, D., Kennedy, B.M., Iezzi, A.M., Fitzgerald, R.H., Austin, A.C., and Johnson, R. (2017), Capturing the Acoustic Radiation Pattern of Strombolian Eruptions using Infrasound Sensors Aboard a Tethered Aerostat, Yasur Volcano, Vanuatu. Geophysical Research Letters, 44 (19), 9672-9680. https://doi.org/10.1002/2017GL074971
Iezzi, A.M. (2020). Exploring Infrasound Wavefields to Characterize Volcanic Eruptions, Ph.D. Dissertation, University of Alaska Fairbanks, Department of Geosciences, 1-192.
Iezzi, A.M. (2015), Lahar Inundation Modeling with the Aid of Historic Flow Deposits at Redoubt Volcano, Cook Inlet, Alaska. Undergraduate Honors Thesis, Connecticut College, Department of Physics, Astronomy and Geophysics, 1-160.

**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.

Get to know CVO: Alex and Infrasound

Get to know CVO: Alex and Infrasound

At the Cascades Volcano Observatory, staff use technical skills and creativity to solve complex problems and innovate for the future. Alex Iezzi uses...

Read Article

Science and Products

Infrasound Propagation Modeling Output for the 1992 eruption of Mount Spurr Infrasound Propagation Modeling Output for the 1992 eruption of Mount Spurr

Data release for the output of infrasound propagation modeling for the August 18th, 1992 eruption of Mount Spurr.
By
Volcano Science Center

Reports of Hearing and Not Hearing the 1992 eruption of Mount Spurr Reports of Hearing and Not Hearing the 1992 eruption of Mount Spurr

Observations of locations where the August 18th, 1992 eruption of Mount Spurr was heard and not heard around Alaska.
By
Volcano Science Center

Swath laser, laser rangefinder, and high-precision analog laser data from gate release and natural release experiments conducted in April 2024 and October 2022, respectively, at the USGS debris-flow flume, HJ Andrews Experimental Forest, Blue River, Orego Swath laser, laser rangefinder, and high-precision analog laser data from gate release and natural release experiments conducted in April 2024 and October 2022, respectively, at the USGS debris-flow flume, HJ Andrews Experimental Forest, Blue River, Orego

The swath laser was tested at the large-scale experimental USGS debris flow flume facility as a potential tool for mass movement detection. The tests were conducted during gate release experiments, where a large volume of sediment was released from a hopper; and during natural release experiments, where a sediment prism was watered until wide-spread Coulomb failure occurred. During the...
By
Volcano Science Center

Laser Rangefinder Data for Surficial Mass Movements in the Cascades Laser Rangefinder Data for Surficial Mass Movements in the Cascades

A laser rangefinder was used to record surficial mass movements at Cascades volcanoes and an experimental debris flow flume. Mass movements such as large lahars and smaller seasonal debris flows can occur at volcanoes in the Cascades. A combination of seismic, infrasound, tripwires, and webcams can be used to detect and characterize these flows. A laser rangefinder can be placed on the...
By
Volcano Science Center
the directions of infrasound from stations at Biscuit Basin and Geyser Hill converge on Giant Geyser
Backazimuth map showing infrasound directions that converge on Giant Geyser, Yellowstone National Park, when it erupted on September 10, 2026
Backazimuth map showing infrasound directions that converge on Giant Geyser, Yellowstone National Park, when it erupted on September 10, 2026
the directions of infrasound from stations at Biscuit Basin and Geyser Hill converge on Giant Geyser

Backazimuth map showing infrasound directions that converge on Giant Geyser, Yellowstone National Park, when it erupted on September 10, 2026

Backazimuth map showing infrasound directions that converge on Giant Geyser, Yellowstone National Park, when it erupted on September 10, 2026

Acoustic signals recorded at infrasound arrays (red inverted triangles) YBB (in Biscuit Basin) and YGH (near Geyser Hill), in Upper Geyser Basin, can be used to determine the direction from which low-frequency acoustic signals originated, also called the backazimuth.  This example is from 9:14 p.m.

By
Volcano Science Center, Yellowstone Volcano Observatory, Yellowstone
the directions of infrasound from stations at Biscuit Basin and Geyser Hill converge on Giant Geyser

Backazimuth map showing infrasound directions that converge on Giant Geyser, Yellowstone National Park, when it erupted on September 10, 2026

Backazimuth map showing infrasound directions that converge on Giant Geyser, Yellowstone National Park, when it erupted on September 10, 2026

Acoustic signals recorded at infrasound arrays (red inverted triangles) YBB (in Biscuit Basin) and YGH (near Geyser Hill), in Upper Geyser Basin, can be used to determine the direction from which low-frequency acoustic signals originated, also called the backazimuth.  This example is from 9:14 p.m.

By
Volcano Science Center, Yellowstone Volcano Observatory, Yellowstone
Plot showing acoustic signals over time Plot showing acoustic signals over time
May 3, 2025, bolide acoustic signal recorded by infrasound station in Yellowstone National Park
Plot showing acoustic signals over time

May 3, 2025, bolide acoustic signal recorded by infrasound station in Yellowstone National Park

May 3, 2025, bolide acoustic signal recorded by infrasound station in Yellowstone National Park

This audio clip is the infrasound recorded during 1 minute on May 3, 2025, at 9:33 p.m.

By
Hawaiian Volcano Observatory, Yellowstone Volcano Observatory
Plot showing acoustic signals over time

May 3, 2025, bolide acoustic signal recorded by infrasound station in Yellowstone National Park

May 3, 2025, bolide acoustic signal recorded by infrasound station in Yellowstone National Park

This audio clip is the infrasound recorded during 1 minute on May 3, 2025, at 9:33 p.m.

By
Hawaiian Volcano Observatory, Yellowstone Volcano Observatory
Seismic and infrasound data for the April 15, 2024, hydrothermal explosion on Porcelain Terrace at Norris Geyser Basin
Seismic and infrasound data for the April 15, 2024, hydrothermal explosion on Porcelain Terrace at Norris Geyser Basin
Seismic and infrasound data for the April 15, 2024, hydrothermal explosion on Porcelain Terrace at Norris Geyser Basin
Seismic and infrasound data for the April 15, 2024, hydrothermal explosion on Porcelain Terrace at Norris Geyser Basin

Seismic and infrasound data for the April 15, 2024, hydrothermal explosion on Porcelain Terrace at Norris Geyser Basin

Seismic and infrasound data for the April 15, 2024, hydrothermal explosion on Porcelain Terrace at Norris Geyser Basin

Seismic and infrasound data for the April 15, 2024, hydrothermal explosion on Porcelain Terrace at Norris Geyser Basin.  Top plot is seismic data from the YNM station, located at the Norris Geyser Basin Museum.  Middle plot is seismic data from station YNB, in the Ragged Hills of Norris Geyser Basin. Bottom plot is infrasound data from station YNB.&nb

By
Volcano Science Center, Yellowstone Volcano Observatory, Yellowstone
Seismic and infrasound data for the April 15, 2024, hydrothermal explosion on Porcelain Terrace at Norris Geyser Basin

Seismic and infrasound data for the April 15, 2024, hydrothermal explosion on Porcelain Terrace at Norris Geyser Basin

Seismic and infrasound data for the April 15, 2024, hydrothermal explosion on Porcelain Terrace at Norris Geyser Basin

Seismic and infrasound data for the April 15, 2024, hydrothermal explosion on Porcelain Terrace at Norris Geyser Basin.  Top plot is seismic data from the YNM station, located at the Norris Geyser Basin Museum.  Middle plot is seismic data from station YNB, in the Ragged Hills of Norris Geyser Basin. Bottom plot is infrasound data from station YNB.&nb

By
Volcano Science Center, Yellowstone Volcano Observatory, Yellowstone
Filter Total Items: 28

Seismoacoustic analysis of possible vent-drying sequence during phreatomagmatic activity on 13 July 2021 at Semisopochnoi Island, Alaska Seismoacoustic analysis of possible vent-drying sequence during phreatomagmatic activity on 13 July 2021 at Semisopochnoi Island, Alaska

Pulse-like infrasound accompanying volcanic phenomena sometimes suggests interaction with water at the crater. We focus on pulse-like infrasound observed at Semisopochnoi Island in the Aleutian Arc, Alaska, during the phreatomagmatic activity on 13 July 2021. Overflight observations confirmed a small, ephemeral water lake on the crater floor in June 2021. We examined temporal variations...
Authors
Dan Muramatsu, John J. Lyons, Hannah R. Dietterich, Mie Ichihara, Alexandra M. Iezzi
By
Volcano Hazards Program, Volcano Science Center

Mount Spurr volcano, August 18, 1992: The eruption heard around Alaska Mount Spurr volcano, August 18, 1992: The eruption heard around Alaska

The August 18, 1992, eruption of Mount Spurr volcano, Alaska, produced an impressive Vulcanian to Subplinian eruption column reaching up to 40 km above sea level that blanketed the nearby city of Anchorage with ash. At the time of the eruption, the Alaska Volcano Observatory received reports of audible sound hundreds of kilometers from the source from a variety of azimuths from the...
Authors
Alexandra M. Iezzi, John Power
By
Volcano Hazards Program, Volcano Science Center

The morphological response to the 13 May 2022 major explosive event at Stromboli volcano, Italy, characterised by high-resolution UAS surveys The morphological response to the 13 May 2022 major explosive event at Stromboli volcano, Italy, characterised by high-resolution UAS surveys

Since 2019, the frequency of major explosive eruptions at Stromboli volcano (Italy) has increased, heightening the exposure of population and scientists to the hazards posed by ejecta. Morphological changes can directly alter the hazard potential associated with these phenomena. Here, we present a quantitative morphological analysis of changes of the crater terrace area linked to the 13...
Authors
Markus Schmid, Ulrich Kueppers, Tullio Ricci, Riccardo Civico, Valeria Cigala, David Fee, Julia E. Gestrich, Alexandra M. Iezzi, Corrado Cimarelli, Caron E.J. Vossen, Richard Michael Buzard, Maurizio Ripepe, Giorgio Lacanna, Donald B. Dingwell
By
Volcano Hazards Program, Volcano Science Center

The first instrumentally detected hydrothermal explosion in Yellowstone National Park The first instrumentally detected hydrothermal explosion in Yellowstone National Park

Hydrothermal explosions are one of the geological hazards most likely to impact people in Yellowstone National Park, but their frequency is poorly known. Infrasound and seismic sensors identified an explosion in Norris Geyser Basin on 15 April 2024, at 14:56 MDT (20:56 UTC)—the first instrumentally detected hydrothermal explosion in the Yellowstone region. The event affected an area tens...
Authors
Michael Poland, Alexandra M. Iezzi, Jamie Farrell, R. Greg Vaughan
By
Natural Hazards Mission Area, Volcano Hazards Program, Astrogeology Science Center, Volcano Science Center, Yellowstone Volcano Observatory

Infrasonic directivity of monopole, dipole, and bipole ground-surface reflected sources Infrasonic directivity of monopole, dipole, and bipole ground-surface reflected sources

Infrasound (acoustic waves below 20 Hz) can be used to detect, locate and quantify activity in the atmosphere such as volcanic eruptions and anthropogenic explosions. Attempts to quantify volcanic eruption parameters such as exit velocity, plume height and mass flow rate using infrasound data depend strongly on assumptions of the acoustic source type. Infrasonic sources may produce...
Authors
Alexandra M. Iezzi, Robin S. Matoza, Emma V. Opper, Keehoon Kim
By
Volcano Hazards Program, Volcano Science Center

Utility of a swath laser rangefinder for characterizing mass movement flow depth and landslide initiation Utility of a swath laser rangefinder for characterizing mass movement flow depth and landslide initiation

Mass movements such as debris flows and landslides are some of the deadliest and most destructive natural hazards occurring mostly in alpine and volcanic settings. With ever-growing populations located downslope from known debris flow channels, early warning systems can help prevent loss of life. Geophysical and technological advances have improved monitoring and detection capabilities...
Authors
Maciej K. Obryk, Emily Christina Bedinger, Alexandra M. Iezzi, Emily H Bryant, Kate E. Allstadt, David L. George, Benjamin B. Mirus
By
Natural Hazards Mission Area, Volcano Hazards Program, Geologic Hazards Science Center, Volcano Science Center

Infrasound for volcano monitoring Infrasound for volcano monitoring

20 hertz [Hz]), but the most energetic band is typically in the infrasound from 0.5 to 20 Hz. Studies of volcanic infrasound and the deployment of infrasound for volcano monitoring have increased rapidly in the past two decades as sensors have improved and as analytical tools have become more widely available. Improved sensors and tools have led to a growing diversity of eruptive...
Authors
John J. Lyons, David Fee, Weston A. Thelen, Alexandra M. Iezzi, Aaron G. Wech
By
Volcano Hazards Program, Volcano Science Center

Monitoring lahars Monitoring lahars

Authors
Weston A. Thelen, John J. Lyons, Alexandra M. Iezzi, Seth C. Moran
By
Volcano Hazards Program, Volcano Science Center

Debris-flow monitoring on volcanoes via a novel usage of a laser rangefinder Debris-flow monitoring on volcanoes via a novel usage of a laser rangefinder

Mount Rainier has had at least 11 large lahars over the last 6,000 years, including one occurring without evidence of eruptive activity. This prompted the creation of a lahar detection system that uses a combination of seismic, infrasound, and tripwires. We test a laser rangefinder placed on a river channel bank for detecting and confirming mass movements flowing past a station as an...
Authors
Alexandra M. Iezzi, Emily H Bryant, Weston Thelen, Craig Gabrielson, Seth C. Moran, Matthew R. Patrick, Edward F. Younger, Maciej K. Obryk
By
Volcano Hazards Program, Volcano Science Center

Recent expansion of the Cascades Volcano Observatory geophysical network at Mount Rainier for improved volcano and lahar monitoring Recent expansion of the Cascades Volcano Observatory geophysical network at Mount Rainier for improved volcano and lahar monitoring

The U.S. Geological Survey Cascades Volcano Observatory (CVO) recently expanded its continuous geophysical monitoring at Mount Rainier, an active stratovolcano in Washington state. CVO monitors volcanoes in Oregon, Washington, and Idaho to characterize volcanic systems and detect unrest. Mount Rainier has a history of large lahar occurrences in the Holocene, including at least one that...
Authors
Rebecca Kramer, Weston Thelen, Alexandra M. Iezzi, Seth C. Moran, Benjamin Pauk
By
Volcano Hazards Program, Volcano Science Center

Lessons learned from the 2022 CONVERSE Monogenetic Volcanism Response Scenario exercise Lessons learned from the 2022 CONVERSE Monogenetic Volcanism Response Scenario exercise

When volcanic unrest occurs, the scientific community can advance fundamental understanding of volcanic systems, but only with coordination before, during, and after the event across academic and governmental agencies. To develop a coordinated response plan, the Community Network for Volcanic Eruption Response (CONVERSE) orchestrated a scenario exercise centered around a hypothetical...
Authors
Yolanda C Lin, Einat Lev, Ria Mukerji, Tobias P. Fischer, Charles B. Connor, Wendy K. Stovall, Michael Poland, Alexandra M. Iezzi, Christelle Wauthier, Judit Gonzalez-Santana, Heather M. Wright, Samantha Wolf, Tobi Kasali
By
Volcano Hazards Program, Volcano Science Center

Introduction to the special section on seismoacoustics and seismoacoustic data fusion Introduction to the special section on seismoacoustics and seismoacoustic data fusion

A variety of geophysical hazards (e.g., volcanic activity, earthquakes, mass movements, marine storms, bolides) and anthropogenic sources (e.g., chemical and nuclear explosions, mining blasts, rocket launches) can release energy as mechanical waves in the ground, ocean, and atmosphere (Arrowsmith et al., 2010; Campus and Christie, 2009). Due to the mechanical coupling between a planetary...
Authors
Fransiska K. Dannemann Dugick, Jordan W. Bishop, Leo Martire, Alexandra M. Iezzi, Jelle D. Assink, Quentin Brissaud, Stephen Arrowsmith
By
Volcano Hazards Program, Volcano Science Center

Non-USGS Publications**

Iezzi, A.M., Matoza R.S., Bishop, J.W., Bhetanabhotla, S., and Fee, D. (2022), Narrow-Band Least-Squares Infrasound Array Processing, Seismological Research Letters: Electronic Seismologist, 93, 5, https://doi.org/10.1785/0220220042
Watson, L.M., Iezzi, A.M., Toney, L., Maher, S.P., Fee, D., McKee, K., Ortiz, H.D., Matoza, R.S., Anderson, J.F., Witsil, A.J.C., Gestrich, J.E., Bishop, J.W., and Johnson, J.B. (2022), Volcano Infrasound: Progress and Future Directions, Bulletin of Volcanology, 84, 44, https://doi.org/10.1007/s00445-022-01544-w
Blom, P.S., Iezzi, A.M., and Euler, G. (2020), Seismoacoustic analysis of underground explosions using the Rayleigh integral, Geophysical Journal International, 223, 1069–1085. https://doi.org/10.1093/gji/ggaa363
Iezzi, A.M., Fee, D., Kim, K., Jolly, A.D., and Matoza, R.S. (2019), Three-Dimensional Acoustic Multipole Waveform Inversion at Yasur Volcano, Vanuatu, Journal of Geophysical Research: Solid Earth, 124, 8679-8703. https://doi.org/10.1029/2018JB017073
Diaz-Moreno, A., Iezzi, A.M., Lamb, O.D., Fee, D., Kim, K., Zuccarello, L., and De Angelis, S. (2019), Volume Flow Rate Estimation for Small Explosions at Mt. Etna, Italy, From Acoustic Waveform Inversion, Geophysical Research Letters, 46, 11071-11079. https://doi.org/10.1029/2019GL084598
Jolly, A.D., Matoza, R.S., Fee, D., Kennedy, B.M., Iezzi, A.M., Fitzgerald, R.H., Austin, A.C., and Johnson, R. (2017), Capturing the Acoustic Radiation Pattern of Strombolian Eruptions using Infrasound Sensors Aboard a Tethered Aerostat, Yasur Volcano, Vanuatu. Geophysical Research Letters, 44 (19), 9672-9680. https://doi.org/10.1002/2017GL074971
Iezzi, A.M. (2020). Exploring Infrasound Wavefields to Characterize Volcanic Eruptions, Ph.D. Dissertation, University of Alaska Fairbanks, Department of Geosciences, 1-192.
Iezzi, A.M. (2015), Lahar Inundation Modeling with the Aid of Historic Flow Deposits at Redoubt Volcano, Cook Inlet, Alaska. Undergraduate Honors Thesis, Connecticut College, Department of Physics, Astronomy and Geophysics, 1-160.

**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.

Get to know CVO: Alex and Infrasound

Get to know CVO: Alex and Infrasound

At the Cascades Volcano Observatory, staff use technical skills and creativity to solve complex problems and innovate for the future. Alex Iezzi uses...

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