I am a research geophysicist with the USGS-USAID Volcano Disaster Assistance Program.
Science and Products
Data of the Hawaiian Volcano Observatory (HVO) Kīlauea Campaign Gravity Network (KCGN)
Data Description Campaign microgravity surveys have been conducted at K?lauea, Hawai‘i (USA), since 1975 (Dzurisin and others, 1980) and, when combined with deformation measurements, enable insights into mass change within the volcano (Jachens and Eaton, 1980; Johnson, 1992; Kauahikaua and Miklius, 2003; Johnson and others, 2010; Bagnardi and others, 2014; Poland and others 2019). For exampl
gTOOLS, an open-source MATLAB program for processing high precision, relative gravity data for time-lapse gravity monitoring
gTOOLS is an open-source software for the processing of relative gravity data. gTOOLS is available in MATLAB and as a compiled executable to be run under the free MATLAB Runtime Compiler. The software has been designed for time-lapse (temporal) gravity monitoring. Although programmed to read the Scintrex CG-5 and CG-6 gravimeters output data files, it can be easily modified to read data files from
A new analysis of caldera unrest through the integration of geophysical data and FEM modeling: The Long Valley caldera case study
The Long Valley Caldera, located at the eastern edge of the Sierra Nevada range in California, has been in a state of unrest since the late 1970s. Seismic, gravity and geodetic data strongly suggest that the source of unrest is an intrusion beneath the caldera resurgent dome. However, it is not clear yet if the main contribution to the deformation comes from pulses of ascending high-pressure hydro
The 2008-2010 subsidence of Dallol volcano on the 2 spreading Erta Ale ridge: InSAR observations and source models
In this work, we study the subsidence of Dallol, an explosive crater and hydrothermal area along the spreading Erta Ale ridge of Afar (Ethiopia). No volcanic products exist at the surface. However, a diking episode in 2004, accompanied by dike-induced faulting, indicates that Dallol is an active volcanic area. The 2004 diking episode was followed by quiescence until subsidence started in 2008. We
Monitoring volcanic deformation
Deformation signals recorded at volcanoes have long been used to infer the processes behind subsurface magma intrusions. Monitoring strategies vary greatly depending on several factors such as the activity of the individual volcano, access, available personnel, and funding.Certain geodetic monitoring methods, such as Electronic Distance Measurements, are inexpensive but require that scientists be
Source model for Sabancaya volcano constrained by DInSAR and GNSS surface deformation observation
Sabancaya is the most active volcano of the Ampato-Sabancaya Volcanic Complex (ASVC) in southern Perú and has been erupting since 2016. The analysis of ascending and descending Sentinel-1 orbits (DInSAR) and Global Navigation Satellite System (GNSS) datasets from 2014 to 2019 imaged a radially symmetric inflating area, uplifting at a rate of 35 to 50 mm/yr and centered 5 km north of Sabancaya. The
Hydrothermal fluid migration due to interaction with shallow magma: Insights from gravity changes before and after the 2015 eruption of Cotopaxi volcano, Ecuador
On August 14, 2015 Cotopaxi Volcano (Ecuador) erupted with several phreatomagmatic explosions after nearly 135 years of quiescence. Unrest began in April 2015 with an increase in the number of daily seismic events and inflation of the flanks of the volcano. Time-lapse gravity measurements started at Cotopaxi volcano in June 2015. Although minor gravity changes were detected prior to eruptive acti
Editorial: Synthetic Aperture Radar and natural hazards: Applications and outlooks
The ability of Synthetic Aperture Radar (SAR) to image the Earth’s surface, even through dense cloud cover and in night-and-day conditions, can facilitate the evaluation and monitoring of natural hazards and the management of natural disasters. The family of SAR satellite sensors orbits the Earth at an altitude ranging from 500 to 800 km, following sun-synchronous, near-polar orbits, slightly incl
Monitoring volcanic deformation
Whereas research in volcano geodesy seeks to push the boundaries of our knowledge of the physics of volcanoes, monitoring looks at changes in volcano behavior to predict when a volcanic crisis might develop. To be effective, geodetic monitoring must be done before, during, and after eruptions and must be integrated with other monitoring techniques. It requires the type of long-term commitment of t
Mass addition at Mount St. Helens, Washington, inferred from repeated gravity surveys
Measurements of subtle changes in the Earth’s gravityfield can provideinformation on the addition/loss of mass (e.g., magma or aqueousfluids) beneath a volcano. In this study, wemeasured gravity at Mount St. Helens from 2010 to 2016 to investigate possible mass changes followingthe 2004–2008 dome-forming eruption. The raw gravity measurements were corrected for changes in themass and shape of Crat
Twenty years (1990–2010) of geodetic monitoring of Galeras volcano (Colombia) from continuous tilt measurements.
Galeras - an andesitic stratovolcano part of the Galeras Volcanic Complex - is one of the most active volcanoes in Colombia. Historic activity is centered on a small-volume cone inside the youngest amphitheater, which breaches the west flank of the volcano. At least 30 confirmed eruption periods have been recorded in the past 480 years, with episodes of unrest ranging from weak fumarolic activity
Science and Products
- Data
Data of the Hawaiian Volcano Observatory (HVO) Kīlauea Campaign Gravity Network (KCGN)
Data Description Campaign microgravity surveys have been conducted at K?lauea, Hawai‘i (USA), since 1975 (Dzurisin and others, 1980) and, when combined with deformation measurements, enable insights into mass change within the volcano (Jachens and Eaton, 1980; Johnson, 1992; Kauahikaua and Miklius, 2003; Johnson and others, 2010; Bagnardi and others, 2014; Poland and others 2019). For exampl - Publications
gTOOLS, an open-source MATLAB program for processing high precision, relative gravity data for time-lapse gravity monitoring
gTOOLS is an open-source software for the processing of relative gravity data. gTOOLS is available in MATLAB and as a compiled executable to be run under the free MATLAB Runtime Compiler. The software has been designed for time-lapse (temporal) gravity monitoring. Although programmed to read the Scintrex CG-5 and CG-6 gravimeters output data files, it can be easily modified to read data files fromA new analysis of caldera unrest through the integration of geophysical data and FEM modeling: The Long Valley caldera case study
The Long Valley Caldera, located at the eastern edge of the Sierra Nevada range in California, has been in a state of unrest since the late 1970s. Seismic, gravity and geodetic data strongly suggest that the source of unrest is an intrusion beneath the caldera resurgent dome. However, it is not clear yet if the main contribution to the deformation comes from pulses of ascending high-pressure hydroThe 2008-2010 subsidence of Dallol volcano on the 2 spreading Erta Ale ridge: InSAR observations and source models
In this work, we study the subsidence of Dallol, an explosive crater and hydrothermal area along the spreading Erta Ale ridge of Afar (Ethiopia). No volcanic products exist at the surface. However, a diking episode in 2004, accompanied by dike-induced faulting, indicates that Dallol is an active volcanic area. The 2004 diking episode was followed by quiescence until subsidence started in 2008. WeMonitoring volcanic deformation
Deformation signals recorded at volcanoes have long been used to infer the processes behind subsurface magma intrusions. Monitoring strategies vary greatly depending on several factors such as the activity of the individual volcano, access, available personnel, and funding.Certain geodetic monitoring methods, such as Electronic Distance Measurements, are inexpensive but require that scientists beSource model for Sabancaya volcano constrained by DInSAR and GNSS surface deformation observation
Sabancaya is the most active volcano of the Ampato-Sabancaya Volcanic Complex (ASVC) in southern Perú and has been erupting since 2016. The analysis of ascending and descending Sentinel-1 orbits (DInSAR) and Global Navigation Satellite System (GNSS) datasets from 2014 to 2019 imaged a radially symmetric inflating area, uplifting at a rate of 35 to 50 mm/yr and centered 5 km north of Sabancaya. TheHydrothermal fluid migration due to interaction with shallow magma: Insights from gravity changes before and after the 2015 eruption of Cotopaxi volcano, Ecuador
On August 14, 2015 Cotopaxi Volcano (Ecuador) erupted with several phreatomagmatic explosions after nearly 135 years of quiescence. Unrest began in April 2015 with an increase in the number of daily seismic events and inflation of the flanks of the volcano. Time-lapse gravity measurements started at Cotopaxi volcano in June 2015. Although minor gravity changes were detected prior to eruptive actiEditorial: Synthetic Aperture Radar and natural hazards: Applications and outlooks
The ability of Synthetic Aperture Radar (SAR) to image the Earth’s surface, even through dense cloud cover and in night-and-day conditions, can facilitate the evaluation and monitoring of natural hazards and the management of natural disasters. The family of SAR satellite sensors orbits the Earth at an altitude ranging from 500 to 800 km, following sun-synchronous, near-polar orbits, slightly inclMonitoring volcanic deformation
Whereas research in volcano geodesy seeks to push the boundaries of our knowledge of the physics of volcanoes, monitoring looks at changes in volcano behavior to predict when a volcanic crisis might develop. To be effective, geodetic monitoring must be done before, during, and after eruptions and must be integrated with other monitoring techniques. It requires the type of long-term commitment of tMass addition at Mount St. Helens, Washington, inferred from repeated gravity surveys
Measurements of subtle changes in the Earth’s gravityfield can provideinformation on the addition/loss of mass (e.g., magma or aqueousfluids) beneath a volcano. In this study, wemeasured gravity at Mount St. Helens from 2010 to 2016 to investigate possible mass changes followingthe 2004–2008 dome-forming eruption. The raw gravity measurements were corrected for changes in themass and shape of CratTwenty years (1990–2010) of geodetic monitoring of Galeras volcano (Colombia) from continuous tilt measurements.
Galeras - an andesitic stratovolcano part of the Galeras Volcanic Complex - is one of the most active volcanoes in Colombia. Historic activity is centered on a small-volume cone inside the youngest amphitheater, which breaches the west flank of the volcano. At least 30 confirmed eruption periods have been recorded in the past 480 years, with episodes of unrest ranging from weak fumarolic activity - News