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Peter Kelly

I am a research geologist based at the Cascades Volcano Observatory. I work to better understand magmatic and hydrothermal systems through research and monitoring of volcanic gas emissions.

I work on US volcanoes as a member of the USGS Volcano Emissions Project and internationally as a member of the USAID-USGS Volcano Disaster Assistance Program (VDAP). This work includes an emphasis on developing and applying new technologies to implement real-time gas monitoring on volcanoes. Prior to joining the USGS in 2008, I spent two years at the University of New Hampshire working on a NOAA-funded project to monitor air pollution.

Education and Certifications

  • M.S., Geochemistry, New Mexico Institute of Mining and Technology, Socorro, NM, 2006

  • B.S., Geology, Northeastern University, Boston, MA, 2003

Science and Products

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Image Collage of Landsat, pollinator, and volcanologist

Characterizing magmatic gases directly in the field

USGS scientist Peter Kelly with the support of the National Innovation Center and partnering with Los Gatos Research, Inc. collaborated to adapt a commercially-available, industrial, in situ HCl-HF analyzer for use in airborne and ground-based measurements of volcanic gases.
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National Innovation Center
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Characterizing magmatic gases directly in the field

USGS scientist Peter Kelly with the support of the National Innovation Center and partnering with Los Gatos Research, Inc. collaborated to adapt a commercially-available, industrial, in situ HCl-HF analyzer for use in airborne and ground-based measurements of volcanic gases.
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Airborne Survey of Gas Emissions from Volcanoes in the Cook Inlet and Northern Alaska Peninsula, 2021

On 16 July 2021, measurements were made of the volcanic gases emitted from Iliamna Volcano, Mount Douglas, Mount Martin, and Mount Mageik (Alaska, USA) from aboard a fixed-wing aircraft. Two zenith-facing differential optical absorption spectrometers were used to measure incident scattered solar ultraviolet radiation while traversing beneath the gas plumes on multiple occasions. These data were us
By
Volcano Science Center

Chemical and isotopic composition of gas, water, and solids from the 2019-2020 water lake in Halema’uma’u Crater, Kīlauea Volcano, Hawaii

Following the 2018 eruption of Kīlauea Volcano (Neal et al, 2019) and the subsequent collapse of the Halema’uma’u crater, groundwater gradually seeped into the newly-deepened crater (Nadeau and others, 2020). Water was first observed in the crater on 7/26/2019, and the water level increased over time until 12/20/2020, when the crater again filled with lava, vaporizing the lake. In the intervening
By
Volcano Science Center, Kīlauea

Provisional Multi-GAS Volcanic Gas Monitoring Data, Obsidian Pool thermal area, Yellowstone National Park

This release presents provisional volcanic gas monitoring data from multi-GAS (multiple Gas Analyzer System) station "YELL_MUD", installed in July 2021 in the Obsidian Pool thermal area, Yellowstone National Park, USA. The multi-GAS station includes gas sensors to measure water vapor, carbon dioxide (CO2), sulfur dioxide (SO2), and hydrogen sulfide (H2S) in gas plumes, as well as meteorologic para
By
Volcano Science Center, Yellowstone

Airborne Volcanic Gas Measurements at Iliamna Volcano, Alaska 2004-2017

This release presents data collected during airborne volcanic gas monitoring flights at Iliamna Volcano, Alaska, that were completed between 2004-2017. Instrumented fixed-wing aircraft were used to collect in situ trace gas measurements of volcanic carbon dioxide (CO2), sulfur dioxide (SO2), and hydrogen sulfide (H2S). The sensor payload also included an upward-looking correlation spectrometer (CO
By
Volcano Science Center

Data from Monitoring Volcanic Gases in Plumes and Ambient Air, Newberry Volcano, Oregon

This release presents volcanic gas monitoring data from periodic surveys and temporary instrument deployments at Newberry Volcano, Oregon. Measurements of plume-gas and ambient air compositions were obtained using single-gas industrial hydrogen sulfide (H2S) sensors and with multi-GAS (multiple Gas Analyzer System; Aiuppa et al., 2005; Shinohara, 2005; Lewicki et al., 2017) instruments that measu
By
Volcano Science Center, Newberry

Volcanic Gas Measurements at Mount Cleveland, Alaska 2016

On 25 July 2016, helicopter-based measurements were made of the volcanic gases emitted from Mount Cleveland, Alaska, USA. An upward-looking differential optical absorption spectroscopy (DOAS) system was used to measure incident scattered solar ultraviolet radiation while traversing beneath the plume on multiple occasions. These data were used to derive volcanic SO2 emission rates. Additionally, a
By
Volcano Hazards Program

Gas and heat emission measurements at Solfatara Plateau Thermal Area, Yellowstone National Park (May-September 2017)

From May to September 2017 measurements of gas and heat emissions were made at Solfatara Plateau Thermal Area, an acid-sulfate, vapor-dominated area in Yellowstone National Park, Wyoming. An eddy covariance system measured half-hourly CO2, H2O and sensible and latent heat fluxes, air temperature and pressure, wind speed and direction and soil moisture. A Multi-GAS instrument measured (0.5 Hz frequ
By
Volcano Hazards Program, Yellowstone

Gas and heat emission measurements in Norris Geyser Basin, Yellowstone National Park (May-October 2016)

From 14 May to 6 October 2016 measurements of gas and heat emissions were made at Bison Flat, an acid-sulfate, vapor-dominated area (0.04-km2) of Norris Geyser Basin, Yellowstone National Park, WY. An eddy covariance system measured half-hourly CO2, H2O and sensible and latent heat fluxes, air temperature and pressure, wind speed and direction, soil moisture and rainfall. A Multi-GAS instrument me
By
Yellowstone

Volcanic Gas Measurements at Mount Cleveland, 14-15 August 2015

Helicopter-based, upward-looking differential optical absorption spectroscopy (DOAS) measurements of scattered solar ultraviolet radiation and Multi-Component Gas Analyzer System (Multi-GAS) measurements of trace gas concentrations were made while traversing beneath and through the gas plume emitted from Mount Cleveland volcano on 14-15 August, 2016. Radiance spectra and gas compositions were reco
By
Volcano Hazards Program
Monitoring for volcanic gases at Newberry Volcano
A MultiGAS instrument measures gases at Newberry Volcano
A MultiGAS instrument measures gases at Newberry Volcano
Monitoring for volcanic gases at Newberry Volcano

A MultiGAS instrument measures gases at Newberry Volcano

A MultiGAS instrument measures gases at Newberry Volcano

Scientists use a MultiGAS instrument (gray, hard-shell case) to measure gas compositions from the East Lake hot spring in the Newberry caldera. The photo was taken on August 3, 2020 just after sunrise. The vapor above the hot spring and lake is typical for cool mornings and is not visible later in the day.

By
Natural Hazards, Volcano Hazards, Cascades Volcano Observatory, Newberry
Monitoring for volcanic gases at Newberry Volcano

A MultiGAS instrument measures gases at Newberry Volcano

A MultiGAS instrument measures gases at Newberry Volcano

Scientists use a MultiGAS instrument (gray, hard-shell case) to measure gas compositions from the East Lake hot spring in the Newberry caldera. The photo was taken on August 3, 2020 just after sunrise. The vapor above the hot spring and lake is typical for cool mornings and is not visible later in the day.

By
Natural Hazards, Volcano Hazards, Cascades Volcano Observatory, Newberry
Picture of the novel HCl/HF analyzer, its components and encasement
A novel HCl/HF analyzer
A novel HCl/HF analyzer
Picture of the novel HCl/HF analyzer, its components and encasement

A novel HCl/HF analyzer

A novel HCl/HF analyzer

State-of-art, cavity-enhanced analyzer to help solve this long-standing technical problem in volcano science, adapted from an industrial instrument. The Off-Axis Integrated Cavity Output Spectroscopy (OA-ICOS) yields a several kilometer path length for absorption. Contains two near-IR tunable diode lasers and is field portable, fast, and precise.

By
National Innovation Center, Volcano Science Center
Picture of the novel HCl/HF analyzer, its components and encasement

A novel HCl/HF analyzer

A novel HCl/HF analyzer

State-of-art, cavity-enhanced analyzer to help solve this long-standing technical problem in volcano science, adapted from an industrial instrument. The Off-Axis Integrated Cavity Output Spectroscopy (OA-ICOS) yields a several kilometer path length for absorption. Contains two near-IR tunable diode lasers and is field portable, fast, and precise.

By
National Innovation Center, Volcano Science Center
Filter Total Items: 26

Development of small uncrewed aerial systems for multi-instrument geophysical data acquisition in active geothermal systems

Small Uncrewed Aerial Systems (sUAS) serve as critical platforms for geophysical data collection at an intermediate scale between lower resolution, regional datasets collected via crewed aerial surveys, and high resolution, but spatially sparse sampling of ground-based data collection methods. Advances in sensor design and sUAS capabilities have led to rapid advances in the amount and type of geop
Authors
Grant Harold Rea-Downing, Claire Bouligand, Jonathan M.G. Glen, Tait E. Earney, Laurie A. Zielinski, Jacob Elliott Anderson, Peter J. Kelly
By
Geology, Minerals, Energy, and Geophysics Science Center

Weak degassing from remote Alaska volcanoes characterized with a new airborne Imaging DOAS instrument and a suite of in situ sensors

Gas emissions from volcanoes occur when volatile species exsolve from magmatic and hydrothermal systems and make their way to the surface. Measurements of emitted gases therefore provide insights into volcanic processes. On 16 July 2021, we made airborne measurements of weak gas plumes emitted from four remote Alaska volcanoes: Iliamna Volcano, Mount Douglas, Mount Martin, and Mount Mageik. Integr
Authors
Christoph Kern, Peter J. Kelly
By
Volcano Hazards Program, Volcano Science Center

Geochemistry and fluxes of gases from hydrothermal features at Newberry Volcano, Oregon, USA

We present the chemical and isotopic compositions of gases and fluxes of CO2 from the hydrothermal features of Newberry Volcano, a large composite volcano located in Oregon's Cascade Range with a summit caldera that hosts two lakes, Paulina and East Lakes. Gas samples were collected from 1982 to 2021 from Paulina Hot Springs (PHS) on the shore of Paulina Lake, East Lake Hot Springs (ELHS) on the s
Authors
Jennifer L. Lewicki, William C. Evans, Steven E. Ingebritsen, Laura E. Clor, Peter J. Kelly, Sara Peek, Robert A. Jensen, Andrew Hunt
By
Ecosystems Mission Area, Water Resources Mission Area, Volcano Hazards Program, Alaska Science Center, Geology, Minerals, Energy, and Geophysics Science Center, Volcano Science Center

Characterizing unrest: A retrospective look at 20 years of gas emissions and seismicity at Iliamna Volcano, Alaska

Episodes of unrest are not as well documented as eruptions at most volcanoes globally. Iliamna is an andesitic stratovolcano in the Cook Inlet of Alaska that has experienced several episodes of unrest. Unrest in 1996 was previously studied. Here we present data from a minor period of unrest between 2002 and 2006, and a more significant period in 2012. None of the episodes led to an eruption. A dik
Authors
Cynthia Werner, John Power, Peter J. Kelly, Stephanie Prejean, Christoph Kern
By
Volcano Hazards Program, Volcano Science Center

UAS-based tools for mapping and monitoring hydrothermal systems: An example from Mammoth Lakes, California

Unoccupied Aerial Systems (UAS) can accommodate a variety of tools for mapping and monitoring hydrothermal systems (e.g., magnetic, gas, photogrammetry, and thermal infrared [TIR]). These platforms offer increased speed, coverage area, and uniformity compared to ground-based measurements, as well as lower flight height – and therefore higher resolution – than occupied aircraft. We adapted a suite
Authors
Laurie Antoinette Zielinski, Jonathan M.G. Glen, Tait E. Earney, Grant H. Rea-Downing, R. Greg Vaughan, Peter J. Kelly, Gordon H. Keller, Branden James Dean, William Schermerhorn
By
Geology, Minerals, Energy, and Geophysics Science Center

Helium-carbon systematics of groundwaters in the Lassen Peak Region

Carbon dioxide emissions from active subaerial volcanoes represent 20–50% of the annual global volcanic CO2 flux (Barry et al., 2014). Passive degassing of carbon from the flanks of volcanoes, and the associated accumulation of dissolved inorganic carbon (DIC) within nearby groundwater, also represents a potentially important, yet poorly constrained flux of carbon to the surface (Werner et al., 20
Authors
Peter Barry, David Bekaert, John Krantz, Saemundor Halldorsson, J. Maarten DeMoor, Tobias Fischer, Cynthia Werner, Peter J. Kelly, Alan Seltzer, Brian Franz, Justin T. Kulongoski
By
Volcano Hazards Program, Volcano Science Center

The petrologic and degassing behavior of sulfur and other magmatic volatiles from the 2018 eruption of Kīlauea, Hawaiʻi: Melt concentrations, magma storage depths, and magma recycling

Kīlauea Volcano’s 2018 lower East Rift Zone (LERZ) eruption produced exceptionally high lava effusion rates and record-setting SO2 emissions. The eruption involved a diverse range of magmas, including primitive basalts sourced from Kīlauea’s summit reservoirs. We analyzed LERZ matrix glasses, melt inclusions, and host minerals to identify melt volatile contents and magma storage depths. The LERZ g
Authors
Allan Lerner, Paul J. Wallace, Thomas Shea, Adrien Mourey, Peter J. Kelly, Patricia Nadeau, Tamar Elias, Christoph Kern, Laura E. Clor, Cheryl Gansecki, R. Lopaka Lee, Lowell Moore, Cynthia A. Werner
By
Ecosystems Mission Area, Volcano Hazards Program, Volcano Science Center, Alaska Science Center

Quantifying gas emissions associated with the 2018 rift eruption of Kīlauea Volcano using ground-based DOAS measurements

Starting on 3 May 2018, a series of eruptive fissures opened in Kīlauea Volcano’s lower East Rift Zone (LERZ). Over the course of the next 3 months, intense degassing accompanied lava effusion from these fissures. Here, we report on ground-based observations of the gas emissions associated with Kīlauea’s 2018 eruption. Visual observations combined with radiative transfer modeling show that ultravi
Authors
Christoph Kern, Allan Lerner, Tamar Elias, Patricia Nadeau, Lacey Holland, Peter J. Kelly, Cynthia Werner, Laura E. Clor, Michael Cappos
By
Volcano Hazards Program, Volcano Science Center

Linking subsurface to surface using gas emission and melt inclusion data at Mount Cleveland volcano, Alaska

Mount Cleveland is one of Alaska's most active volcanoes, yet little is known about the magmatic system driving persistent and dynamic volcanic activity. Volcanic gas and melt inclusion (MI) data from 2016 were combined to investigate shallow magmatic processes. SO2 emission rates were between 166 and 324 t/day and the H2O/SO2 was 600 ± 53, whereas CO2 and H2S were below detection. Olivine‐, clino
Authors
Cynthia Werner, Daniel J. Rasmussen, Terry Plank, Peter J. Kelly, Christoph Kern, Taryn Lopez, Jonas Gliss, John Power, Diana Roman, Pavel Izbekov, John J. Lyons
By
Volcano Hazards Program, Volcano Science Center

Chemical evaluation of water and gases collected from hydrothermal systems located in the central Aleutian arc, August 2015

Five volcanic-hydrothermal systems in the central Aleutians Islands were sampled for water and gas geochemistry in 2015 to provide baseline data to help predict future volcanic unrest. Some areas had not been sampled in 20–30 years (Makushin volcano, Geyser Bight), and other areas had minimal to no prior sampling (Tana volcano and Fisher Caldera). The chemical and isotopic data of the waters show
Authors
Cynthia A. Werner, Christoph Kern, Peter J. Kelly
By
Volcano Hazards Program, Volcano Science Center

The emissions of CO2 and other volatiles from the world’s subaerial volcanoes

Volcanoes are the main pathway to the surface for volatiles that are stored within the Earth. Carbon dioxide (CO2) is of particular interest because of its potential for climate forcing. Understanding the balance of CO2 that is transferred from the Earth’s surface to the Earth’s interior, hinges on accurate quantification of the long-term emissions of volcanic CO2 to the atmosphere. Here we presen
Authors
Tobias P. Fischer, Santiago Arellano, Simon Carn, Alessandro Aiuppa, Bo Galle, Patrick Allard, Taryn Lopez, Hiroshi Shinohara, Peter J. Kelly, Cynthia Werner, Carlo Cardelini, Giovanni Chiodini
By
Volcano Hazards Program, Volcano Science Center

The 2017-19 activity at Mount Agung in Bali (Indonesia): Intense unrest, monitoring, crisis response, evacuation, and eruption

After 53 years of quiescence, Mount Agung awoke in August 2017, with intense seismicity, measurable ground deformation, and thermal anomalies in the summit crater. Although the seismic unrest peaked in late September and early October, the volcano did not start erupting until 21 November. The most intense explosive eruptions with accompanying rapid lava effusion occurred between 25 and 29 November
Authors
D.K. Syahbana, K. Kasbani, G. Suantika, O. Prambada, A. Andreas, U. Saing, S. Kunrat, S.L. Andreastuti, S. Martanto, E. Kriswati, Y. Suparman, H. Humaida, Sarah E. Ogburn, Peter J. Kelly, John Wellik, Heather Wright, Jeremy D. Pesicek, Rick Wessels, Christoph Kern, Michael Lisowski, Angela K. Diefenbach, Michael P. Poland, Francois Beauducel, R. Greg Vaughan, John S. Pallister, Jacob B. Lowenstern
By
Volcano Hazards Program, Volcano Science Center
Development of a field-portable helium isotope detector for continuous, real-time monitoring of active volcanoes

Development of a field-portable helium isotope detector for continuous, real-time monitoring of active volcanoes

Scientists from the USGS Volcano Hazards Program have been developing various technologies that allow for real-time and continuous measurements of gas...

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New Volcanic Gas Monitoring Station Installed at Mount St. Helens.

New Volcanic Gas Monitoring Station Installed at Mount St. Helens.

This summer, a new monitoring station was installed on the lava dome in the crater of Mount St. Helens to "sniff" volcanic gases.

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