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
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.
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
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
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
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
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
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
Filter Total Items: 22
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
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
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
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
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
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
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
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
The 2018 rift eruption and summit collapse of Kilauea Volcano
In 2018, Kīlauea Volcano experienced its largest lower East Rift Zone (LERZ) eruption and caldera collapse in at least 200 years. After collapse of the Pu'u 'Ō'ō vent on 30 April, magma propagated downrift. Eruptive fissures opened in the LERZ on 3 May, eventually extending ~6.8 km. A 4 May earthquake (M6.9) produced ~5 m of fault slip. Lava erupted at rates exceeding 100 m3/s, eventually coveri
Insights into the mechanisms of phreatic eruptions from continuous high frequency volcanic gas monitoring: Rincón de la Vieja volcano, Costa Rica
Understanding the trigger mechanisms of phreatic eruptions is key to mitigating the effects of these hazardous but poorly forecastable volcanic events. It has recently been established that high-rate volcanic gas observations are potentially very suitable to identifying the source processes driving phreatic eruptions, and to eventually detecting precursory changes prior to individual phreatic blas
Evolution of the 2015 Cotopaxi eruption revealed by combined geochemical & seismic observations
Through integration of multiple data streams to monitor volcanic unrest scientists are able to make more robust eruption forecast and to obtain a more holistic interpretation of volcanic systems. We examined gas emission and gas geochemistry, seismic and petrologic data recorded during the 2015 unrest of Cotopaxi (Ecuador) in order to decipher the origin and temporal evolution of this eruption. Id
Multi-year high-frequency hydrothermal monitoring of selected high-threat Cascade Range volcanoes
From 2009 to 2015 the U.S. Geological Survey (USGS) systematically monitored hydrothermal behavior at selected Cascade Range volcanoes in order to define baseline hydrothermal and geochemical conditions. Gas and water data were collected regularly at 25 sites on 10 of the highest-risk volcanoes in the Cascade Range. These sites include near-summit fumarole groups and springs/streams that show clea
Science and Products
- Science
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. - Data
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 (COData 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 measuVolcanic 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, aGas 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 frequGas 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 meVolcanic 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 - Multimedia
- Publications
Filter Total Items: 22
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 sHelium-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., 20The 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 gQuantifying 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 ultraviLinking 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‐, clinoChemical 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 showThe 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 presenThe 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 NovemberThe 2018 rift eruption and summit collapse of Kilauea Volcano
In 2018, Kīlauea Volcano experienced its largest lower East Rift Zone (LERZ) eruption and caldera collapse in at least 200 years. After collapse of the Pu'u 'Ō'ō vent on 30 April, magma propagated downrift. Eruptive fissures opened in the LERZ on 3 May, eventually extending ~6.8 km. A 4 May earthquake (M6.9) produced ~5 m of fault slip. Lava erupted at rates exceeding 100 m3/s, eventually coveriInsights into the mechanisms of phreatic eruptions from continuous high frequency volcanic gas monitoring: Rincón de la Vieja volcano, Costa Rica
Understanding the trigger mechanisms of phreatic eruptions is key to mitigating the effects of these hazardous but poorly forecastable volcanic events. It has recently been established that high-rate volcanic gas observations are potentially very suitable to identifying the source processes driving phreatic eruptions, and to eventually detecting precursory changes prior to individual phreatic blasEvolution of the 2015 Cotopaxi eruption revealed by combined geochemical & seismic observations
Through integration of multiple data streams to monitor volcanic unrest scientists are able to make more robust eruption forecast and to obtain a more holistic interpretation of volcanic systems. We examined gas emission and gas geochemistry, seismic and petrologic data recorded during the 2015 unrest of Cotopaxi (Ecuador) in order to decipher the origin and temporal evolution of this eruption. IdMulti-year high-frequency hydrothermal monitoring of selected high-threat Cascade Range volcanoes
From 2009 to 2015 the U.S. Geological Survey (USGS) systematically monitored hydrothermal behavior at selected Cascade Range volcanoes in order to define baseline hydrothermal and geochemical conditions. Gas and water data were collected regularly at 25 sites on 10 of the highest-risk volcanoes in the Cascade Range. These sites include near-summit fumarole groups and springs/streams that show clea - News