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Volcano Hazards Program

Find U.S. Volcano

There are about 170 potentially active volcanoes in the U.S. The mission of the USGS Volcano Hazards Program is to enhance public safety and minimize social and economic disruption from volcanic unrest and eruption through our National Volcano Early Warning System. We deliver forecasts, warnings, and information about volcano hazards based on a scientific understanding of volcanic behavior.

Learn more about NVEWS

Volcano Activity Notifications

Ash-rich plume rises out of Halemaʻumaʻu Crater, Kilauea Volcano Hawaiʻi

USGS Volcano Observatories release regular updates and notifications to communicate increases or decreases in volcanic activity and explain unusual or hazardous circumstances. 

Get Latest Updates

Volcano Hazards Assessments

Mount Rainier seen from Puyallup, Washington

Long-term hazards assessments identify locations at risk from volcanic hazards. They are released as high-resolution hazards-zonation maps with accompanying explanations, which help guide eruption preparedness plans.

View Assessments

U.S. Volcano Observatories

Volcano Observatory staff monitor, research, and issue formal notices of activity for volcanoes in assigned geographic areas. Scientists also assess volcano hazards and work with communities to prepare for volcanic eruptions.

Learn More

News

Photo & Video Chronology — April 9, 2026 — Kīlauea summit episode 44

Photo & Video Chronology — April 9, 2026 — Kīlauea summit episode 44

Volcano Watch — Caldera clues: tephra deposits from Kīlauea’s past

Volcano Watch — Caldera clues: tephra deposits from Kīlauea’s past

New open access articles on Mauna Loa 2022 eruption

New open access articles on Mauna Loa 2022 eruption

View All

Publications

Yellowstone Volcano Observatory 2024 annual report Yellowstone Volcano Observatory 2024 annual report

The Yellowstone Volcano Observatory (YVO) monitors volcanic and hydrothermal activity associated with the Yellowstone magmatic system, carries out research into magmatic processes occurring beneath Yellowstone Caldera, and issues timely warnings and guidance related to potential future geologic hazards. YVO is a collaborative consortium that includes the U.S. Geological Survey (USGS)...
Authors
Yellowstone Volcano Observatory
By
Volcano Hazards Program, Volcano Science Center

Determining Volcanic Risk in Auckland (DEVORA) Research Programme—A transdisciplinary approach to address the challenge of distributed volcanism in an urban environment Determining Volcanic Risk in Auckland (DEVORA) Research Programme—A transdisciplinary approach to address the challenge of distributed volcanism in an urban environment

The Determining Volcanic Risk in Auckland (DEVORA) Research Programme was launched in 2008 to address the challenges associated with monogenetic volcanism in an urban setting and to enhance volcanic risk management in Tāmaki Makaurau Auckland in Aotearoa New Zealand. It is a multi-agency, increasingly transdisciplinary (defined here as research that transcends traditional disciplinary...
Authors
Jan M. Lindsay, Elaine R. Smid, Natalie Balfour, Natalia I. Deligne, Angela Doherty, Annahlise Hall, Tracy Howe, Gill Jolly, Graham Leonard, Kate Lewis, Craig A. Miller, Ema Nersezova, Ross Roberts, Richard E. Smith, Thomas Stolberger, Kelvin Tapuke, Thomas M. Wilson
By
Volcano Hazards Program, Volcano Science Center

Advances in volcano monitoring driven by the first decade of Sentinel-1 observations Advances in volcano monitoring driven by the first decade of Sentinel-1 observations

Sentinel-1 has transformed how satellite radar data (SAR and InSAR) are used in volcanology. The systematic, long-term archive and open-access policy means that volcano observatories and research organisations have invested in integrating Sentinel-1 datasets into their monitoring systems. We identify 233 high priority volcanoes and estimate that Sentinel-1 data has been used in peer...
Authors
Juliet Biggs, Nantheera Anantrasirichai, Kyle R. Anderson, Valerie Cayol, Edna W. Dualeh, Quentin Dumont, Susanna K. Ebmeier, Jean Luc Froger, Matthew Gaddes, Federico Galleto, Pablo J. Gonzales, Ian Hamling, Andrew Hooper, Milan Lazecky, Camila Novoa Lizama, Matthew E. Pritchard
By
Volcano Hazards Program, Volcano Science Center
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Melt Inclusion Page

Reprints of two review articles on melt inclusions

Lowenstern, J.B., 2003, Melt inclusions come of age: Volatiles, Volcanoes, and Sorby's Legacy, In: B. De Vivo and R.J. Bodnar (eds). Melt Inclusions in Volcanic Systems: Methods, Applications and Problems. Developments in Volcanology 5, Elsevier Press, Amsterdam, pp. 1-22.

A 6 Megabyte pdf version of this website (the original review article) is available here.

The Melt Inclusion Page

About Melt Inclusions

Formation of Silicate-Melt Inclusions

  • Types of Inclusions,
  • Entrapment Mechanisms,
  • Leaked or "Hourglass Inclusions"
  • Does the Melt Inclusion Trap Representative Liquid?

    • Changes in Melt Inclusions After Entrapment

  • Volumetric Behavior
  • Other Origins of Bubbles
  • Crystallization
  • Diffusional Reequilibration

    • Techniques for Study

  • Sample Preparation
  • Electron Microprobe Analysis,
  • Ion Microprobe
  • Fourier Transform Infrared Spectroscopy
  • Other Analytical Techniques
  • Heating Stage

    • Concentrations of Dissolved Volatiles in MI

    Evidence for Fluid Saturation and Degassing

  • Mass-Balance Contraints
  • Fluid Solubility and Buffering Paths,
  • Trapped Vapors and Hypersaline Liquids

    • Petrologic and Stratigraphic Studies

  • Magma Mixing and Crystal Fractionation
  • Experimental Petrology
  • Stratigraphic Correlations

    • Melt Inclusions in Granites and Xenolithic Ejecta

    Summary

    Acknowledgements

    References

    Adapted from: Lowenstern, J.B.(1995) Applications of silicate melt inclusions to the study of magmatic volatiles. In: Thompson, J.F.H. (ed.) Magmas, Fluid and Ore Deposits. Mineralogical Association of Canada Short Course 23, 71-99.

    This article is adapted from Chapter 4 of Volume 23 of the Geological Association of Canada/ Mineralogical Association of Canada (GAC/MAC) Short Course Series. For more information, please refer to: Lowenstern (1995)

    Table 1: Data obtainable and not obtainable from silicate-melt inclusions.

    Table 2: Volatile concentrations in a variety of recently studied silicic magmas, as determined by analysis of silicate MI.

    Table 3. Summary of recent studies of volatile concentrations and saturation pressures in unleaked MI from high-silica rhyolites.

    Figure 1. Melt inclusions in quartz.

    Figure 2. Growth forms of crystals that trap MI.

    Figure 3. Hourglass inclusions.

    Figure 4. PT behavior of MI.

    Figure 5. Homogenization of an MI.

    Figure 6. Decrepitation of an MI.

    Figure 7. Crystallization of an MI.

    Figure 8. H2O vs. CO2 for a group of MI from the Pine Grove system, UT.

    Figure 9. Features within a vapor bubble.

    Other Photos of Melt Inclusions. Cool Pics!

    Volcano Hazards Program | U.S. Geological Survey Skip to main content
    U.S. flag

    An official website of the United States government

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    The map displays volcanoes, earthquakes, monitoring instruments, and past lava flows.

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    Earthquake Plots
    To view an earthquake cross-sectional plot, click "Draw Plot" to start drawing on the map. Once the plot area is selected, click on "View Plot" to view chart or "Clear Plot" to start over.

    Results
    Filters

    Learn More

    The map displays volcanoes, earthquakes, monitoring instruments, and past lava flows.

    Get Help

    Earthquake Plots
    To view an earthquake cross-sectional plot, click "Draw Plot" to start drawing on the map. Once the plot area is selected, click on "View Plot" to view chart or "Clear Plot" to start over.

    Settings

    x

    Map Legend

    x

    Map Legend

    Results

    Volcano Hazards Program

    Find U.S. Volcano

    There are about 170 potentially active volcanoes in the U.S. The mission of the USGS Volcano Hazards Program is to enhance public safety and minimize social and economic disruption from volcanic unrest and eruption through our National Volcano Early Warning System. We deliver forecasts, warnings, and information about volcano hazards based on a scientific understanding of volcanic behavior.

    Learn more about NVEWS

    Volcano Activity Notifications

    Ash-rich plume rises out of Halemaʻumaʻu Crater, Kilauea Volcano Hawaiʻi

    USGS Volcano Observatories release regular updates and notifications to communicate increases or decreases in volcanic activity and explain unusual or hazardous circumstances. 

    Get Latest Updates

    Volcano Hazards Assessments

    Mount Rainier seen from Puyallup, Washington

    Long-term hazards assessments identify locations at risk from volcanic hazards. They are released as high-resolution hazards-zonation maps with accompanying explanations, which help guide eruption preparedness plans.

    View Assessments

    U.S. Volcano Observatories

    Volcano Observatory staff monitor, research, and issue formal notices of activity for volcanoes in assigned geographic areas. Scientists also assess volcano hazards and work with communities to prepare for volcanic eruptions.

    Learn More

    News

    Photo & Video Chronology — April 9, 2026 — Kīlauea summit episode 44

    Photo & Video Chronology — April 9, 2026 — Kīlauea summit episode 44

    Volcano Watch — Caldera clues: tephra deposits from Kīlauea’s past

    Volcano Watch — Caldera clues: tephra deposits from Kīlauea’s past

    New open access articles on Mauna Loa 2022 eruption

    New open access articles on Mauna Loa 2022 eruption

    View All

    Publications

    Yellowstone Volcano Observatory 2024 annual report Yellowstone Volcano Observatory 2024 annual report

    The Yellowstone Volcano Observatory (YVO) monitors volcanic and hydrothermal activity associated with the Yellowstone magmatic system, carries out research into magmatic processes occurring beneath Yellowstone Caldera, and issues timely warnings and guidance related to potential future geologic hazards. YVO is a collaborative consortium that includes the U.S. Geological Survey (USGS)...
    Authors
    Yellowstone Volcano Observatory
    By
    Volcano Hazards Program, Volcano Science Center

    Determining Volcanic Risk in Auckland (DEVORA) Research Programme—A transdisciplinary approach to address the challenge of distributed volcanism in an urban environment Determining Volcanic Risk in Auckland (DEVORA) Research Programme—A transdisciplinary approach to address the challenge of distributed volcanism in an urban environment

    The Determining Volcanic Risk in Auckland (DEVORA) Research Programme was launched in 2008 to address the challenges associated with monogenetic volcanism in an urban setting and to enhance volcanic risk management in Tāmaki Makaurau Auckland in Aotearoa New Zealand. It is a multi-agency, increasingly transdisciplinary (defined here as research that transcends traditional disciplinary...
    Authors
    Jan M. Lindsay, Elaine R. Smid, Natalie Balfour, Natalia I. Deligne, Angela Doherty, Annahlise Hall, Tracy Howe, Gill Jolly, Graham Leonard, Kate Lewis, Craig A. Miller, Ema Nersezova, Ross Roberts, Richard E. Smith, Thomas Stolberger, Kelvin Tapuke, Thomas M. Wilson
    By
    Volcano Hazards Program, Volcano Science Center

    Advances in volcano monitoring driven by the first decade of Sentinel-1 observations Advances in volcano monitoring driven by the first decade of Sentinel-1 observations

    Sentinel-1 has transformed how satellite radar data (SAR and InSAR) are used in volcanology. The systematic, long-term archive and open-access policy means that volcano observatories and research organisations have invested in integrating Sentinel-1 datasets into their monitoring systems. We identify 233 high priority volcanoes and estimate that Sentinel-1 data has been used in peer...
    Authors
    Juliet Biggs, Nantheera Anantrasirichai, Kyle R. Anderson, Valerie Cayol, Edna W. Dualeh, Quentin Dumont, Susanna K. Ebmeier, Jean Luc Froger, Matthew Gaddes, Federico Galleto, Pablo J. Gonzales, Ian Hamling, Andrew Hooper, Milan Lazecky, Camila Novoa Lizama, Matthew E. Pritchard
    By
    Volcano Hazards Program, Volcano Science Center
    View All
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