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Monitoring lahars

IntroductionLahars, or debris flows that originate from a volcano (Pierson and Scott, 1985; Pierson, 1995), are among the most destructive, far-reaching, and persistent hazards on stratovolcanoes. Lahars may be triggered by syneruptive rapid melting of snow and ice, lake breakouts, or heavy rains in conjunction with large eruptive columns. Alternatively, lahars can follow eruptions, when...
Authors
Weston A. Thelen, John J. Lyons, Alexandra M. Iezzi, Seth C. Moran

Tracking surface changes caused by volcanic activity

IntroductionDynamic volcanic landscapes produce various changes at the surface of volcanic edifices. For example, rising magma can induce thermal emissions, formation of ground cracks, and variations in glacier and edifice morphology; volcanic deposits from eruptions can transform the land surface with tephra fall, pyroclastic flows, lava flows and domes, and lahars; and geomorphic...
Authors
Tim R. Orr, Hannah R. Dietterich, Michael P. Poland

Streams, springs, and volcanic lakes for volcano monitoring

IntroductionVolcanic unrest can trigger appreciable change to surface waters such as streams, springs, and volcanic lakes. Magma degassing produces gases and soluble salts that are absorbed into groundwater that feeds streams and lakes. As magma ascends, the amount of heat and degassing will increase, and so will any related geochemical and thermal signal. Subsurface magma movement can...
Authors
Steven E. Ingebritsen, Shaul Hurwitz

Volcanic gas monitoring

IntroductionAs magma rises through the crust, decreasing pressure conditions allow volatiles to exsolve from the magma. These volatiles then migrate upward through the crust, where they can be stored at shallower levels or escape to the atmosphere. Rising magma also heats rock masses beneath volcanic centers, causing water in shallow aquifers and hydrothermal systems to boil and release...
Authors
Jennifer L. Lewicki, Christoph Kern, Peter J. Kelly, Patricia A. Nadeau, Tamar Elias, Laura E. Clor

Ground deformation and gravity for volcano monitoring

IntroductionWhen magma accumulates or migrates, it can cause pressurization and related ground deformation. Characterization of surface deformation provides important constraints on the potential for future volcanic activity, especially in combination with seismic activity, gas emissions, and other indicators. A wide variety of techniques and instrument types have been applied to the...
Authors
Emily K. Montgomery-Brown, Kyle R. Anderson, Ingrid A. Johanson, Michael P. Poland, Ashton F. Flinders

Infrasound for volcano monitoring

IntroductionVolcanic eruptions produce acoustic waves when volcanic gases and hot material rapidly expand in the atmosphere. Volcanic activity can produce acoustic signals with a wide range of frequencies, from very long period (>10 seconds) to audible (>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...
Authors
John J. Lyons, David Fee, Weston A. Thelen, Alexandra M. Iezzi, Aaron G. Wech

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...

The Khonkho tephra: A large-magnitude volcanic eruption coincided with the rise of Tiwanaku in the Andes

We report a tephra deposit in the southern Lake Titicaca Basin, Bolivia, which was deposited by a major, previously unrecognized eruption sometime between AD 400 and 720. Archaeological data suggest these centuries were characterized by a substantial community migration to Tiwanaku, where social interaction networks gave birth to one of the Andes’ first large complex societies. Here we...
Authors
Erik J. Marsh, Christopher Harpel, David Damby

Physics-based forecasts of eruptive vent locations at calderas

Constraining stresses in the Earth's crust in volcanic regions is critical for understanding many mechanical processes related to eruptive activity. Dike pathways, in particular, are shaped by the orientation of principal stress axes. Therefore, accurate models of dike trajectories and future vent locations rely on accurate estimates of stresses in the subsurface. This work presents a...
Authors
Lorenzo Mantiloni, Eleanora Rivalta, Kyle R. Anderson, Timothy W. Davis, Luigi Passarelli

Two-million-year eruptive history of Laguna del Maule volcanic field

The Laguna del Maule (LdM) volcanic field, which surrounds the 54-km2 lake of that name, covers ∼500 km2 of mountainous glaciated terrain with Quaternary lavas and tuffs that extend 40 km westward from the Argentine frontier and 30 km north-south from the Río Campanario to Laguna Fea. Complementing recent investigations of postglacial volcanism and the ongoing geophysical unrest around...
Authors
Edward Hildreth, Judith E. Fierstein

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 Obryk

Reexamining the Honolulu Volcanics: Hawai‘i's classic case of rejuvenation volcanism

Rejuvenated volcanism is a worldwide phenomenon occurring on many oceanic islands in all of the major ocean basins. This plume-related volcanism follows the main edifice-building stage after a hiatus of variable duration (e.g. 0.6–2 Myrs in Hawai'i). The Honolulu Volcanics (HV), the classic case of rejuvenated volcanism, involved monogenetic eruptions from at least 48 vent areas...
Authors
Michael O. Garcia, Marc D. Norman, Brian Jicha, Kendra J. Lynn, Peng Jiang
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