Over several weeks in April, USGS Hawaiian Volcano Observatory scientists, along with visiting scientist from other volcano observatories, conducted the annual Kīlauea microgravity survey.
2019 Kīlauea Disaster Supplemental Funding: Gravity Monitoring
Active
By Supplemental Appropriations for Disaster Recovery Activities
June 21, 2022
Through the Additional Supplemental Appropriations for Disaster Relief Act of 2019 (H.R. 2157), the USGS received Supplemental funding to support recovery and rebuilding activities in the wake of the 2018 Kīlauea volcano eruption. Supplemental funding will enable the USGS to conduct scientific investigations of the current state of Kīlauea to properly interpret the data from the monitoring networks and characterize the ongoing and future threats and hazards to Hawai‘i Volcanoes National Park and surrounding communities. Measuring small changes in gravity provides an important means of detecting changes in Kīlauea’s magma plumbing system over time.
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The gravitational pull at the surface of the Earth is controlled in part by the distribution of mass beneath the ground. If that mass changes—for example, due to variations in the amount of magma in a subsurface reservoir—then the gravity will also change. Magma accumulation is accompanied by an increase in gravity because more mass is present beneath the surface, while magma drainage causes a decrease in the gravitational pull at the surface.
Gravity change has been measured at Kīlauea since 1975, and these data have provided important insights into subsurface magma transport and storage. It is common to see gravity increases at Kīlauea even when the ground is not inflating. This result suggests that magma is accumulating in void space—probably networks of interconnected cracks—and so it is not causing surface uplift seismicity due to increases in pressure. The only way to detect such activity is by monitoring gravity variations. For example, surveys in November 2018 and March 2019 showed a gravity increase during that time, but surface uplift was not detected until shortly after the second survey, in March 2019. These data were interpreted to indicate that magma was accumulating in void space that was created during the 2018 collapse of Kīlauea’s summit, and that by March 2019 enough magma had filled this space that the system began to pressurize and inflate.
Gravity can also be measured by continuous sensors. Prior to the 2018 collapse of Kīlauea’s summit, a gravimeter on the rim of the lava lake in Halemaʻumaʻu measured changes that were associated with the rise and fall of the lava lake. When these data were combined with measurements of lava level and the shape of the crater, it was possible to calculate the density of the lava lake. Surprisingly, the density was found to be about the same as water, which indicates that the lava lake was very rich in gas bubbles.
Sources/Usage: Public Domain. View Media Details
In April 2022, USGS and collaborating scientists from the Royal Dutch Meteorological Institute (KNMI) conducted a full survey of the Kīlauea summit gravity network. A preliminary comparison of these data with those collected in 2019 show a very large gravity increase that is related to magma accumulation in the shallow reservoir beneath Kīlauea Caldera plus the growth of the lava lake in the 2018 collapse pit since the resumption of eruptive activity in 2020. Future work will attempt to understand the relative contributions of these two sources of gravity increase.
Also in April 2022, three new continuous gravity stations were installed on the caldera floor, and an existing site was improved with new infrastructure to protect the sensitive equipment from volcanic gases. The gravimeter for one of the new stations was purchased with funding from Additional Supplemental Appropriations for Disaster Relief Act of 2019 (H.R. 2157). Two of the other gravimeters were made available via long-term equipment loans to HVO from Rensselaer Polytechnic Institute (RPI) and from KNMI. The existing gravimeter recorded an anomalous signal prior to the onset of eruptive activity at Kīlauea in late December 2021, but it is difficult to interpret data recorded by a single station. Data from the new network should provide a better understanding of subsurface magma movement associated with intrusions and eruptions at Kīlauea.
Sources/Usage: Public Domain. View Media Details
Kīlauea Gravity Survey - April 2022
Over several weeks in April, USGS Hawaiian Volcano Observatory scientists, along with visiting scientist from other volcano observatories, conducted the annual Kīlauea microgravity survey.
Continuous gravimeter
A continuous gravimeter in an enclosure designed by Hawaiian Volcano Observatory staff. USGS image.
A continuous gravimeter in an enclosure designed by Hawaiian Volcano Observatory staff. USGS image.
Campaign gravity measurement
A campaign gravity measurement being made near Keanakākoʻi Crater, within Hawaiʻi Volcanoes National Park. Kīlauea's summit eruption plume and Mauna Loa are visible in the background. USGS image.
A campaign gravity measurement being made near Keanakākoʻi Crater, within Hawaiʻi Volcanoes National Park. Kīlauea's summit eruption plume and Mauna Loa are visible in the background. USGS image.
Hawaiian Volcano Observatory continuous gravimeter station on Kīlauea
A Hawaiian Volcano Observatory continuous gravimeter station on Kīlauea Volcano. The continuous gravimeter is located within the weather-proof enclosure in the foreground of the photograph. Power systems for the gravimeter and continuous GPS are visible in the center of the photograph and consist of solar panels and batteries in weather-proof enclosures.
A Hawaiian Volcano Observatory continuous gravimeter station on Kīlauea Volcano. The continuous gravimeter is located within the weather-proof enclosure in the foreground of the photograph. Power systems for the gravimeter and continuous GPS are visible in the center of the photograph and consist of solar panels and batteries in weather-proof enclosures.
Through the Additional Supplemental Appropriations for Disaster Relief Act of 2019 (H.R. 2157), the USGS received Supplemental funding to support recovery and rebuilding activities in the wake of the 2018 Kīlauea volcano eruption. Supplemental funding will enable the USGS to conduct scientific investigations of the current state of Kīlauea to properly interpret the data from the monitoring networks and characterize the ongoing and future threats and hazards to Hawai‘i Volcanoes National Park and surrounding communities. Measuring small changes in gravity provides an important means of detecting changes in Kīlauea’s magma plumbing system over time.
Sources/Usage: Public Domain. View Media Details
The gravitational pull at the surface of the Earth is controlled in part by the distribution of mass beneath the ground. If that mass changes—for example, due to variations in the amount of magma in a subsurface reservoir—then the gravity will also change. Magma accumulation is accompanied by an increase in gravity because more mass is present beneath the surface, while magma drainage causes a decrease in the gravitational pull at the surface.
Gravity change has been measured at Kīlauea since 1975, and these data have provided important insights into subsurface magma transport and storage. It is common to see gravity increases at Kīlauea even when the ground is not inflating. This result suggests that magma is accumulating in void space—probably networks of interconnected cracks—and so it is not causing surface uplift seismicity due to increases in pressure. The only way to detect such activity is by monitoring gravity variations. For example, surveys in November 2018 and March 2019 showed a gravity increase during that time, but surface uplift was not detected until shortly after the second survey, in March 2019. These data were interpreted to indicate that magma was accumulating in void space that was created during the 2018 collapse of Kīlauea’s summit, and that by March 2019 enough magma had filled this space that the system began to pressurize and inflate.
Gravity can also be measured by continuous sensors. Prior to the 2018 collapse of Kīlauea’s summit, a gravimeter on the rim of the lava lake in Halemaʻumaʻu measured changes that were associated with the rise and fall of the lava lake. When these data were combined with measurements of lava level and the shape of the crater, it was possible to calculate the density of the lava lake. Surprisingly, the density was found to be about the same as water, which indicates that the lava lake was very rich in gas bubbles.
Sources/Usage: Public Domain. View Media Details
In April 2022, USGS and collaborating scientists from the Royal Dutch Meteorological Institute (KNMI) conducted a full survey of the Kīlauea summit gravity network. A preliminary comparison of these data with those collected in 2019 show a very large gravity increase that is related to magma accumulation in the shallow reservoir beneath Kīlauea Caldera plus the growth of the lava lake in the 2018 collapse pit since the resumption of eruptive activity in 2020. Future work will attempt to understand the relative contributions of these two sources of gravity increase.
Also in April 2022, three new continuous gravity stations were installed on the caldera floor, and an existing site was improved with new infrastructure to protect the sensitive equipment from volcanic gases. The gravimeter for one of the new stations was purchased with funding from Additional Supplemental Appropriations for Disaster Relief Act of 2019 (H.R. 2157). Two of the other gravimeters were made available via long-term equipment loans to HVO from Rensselaer Polytechnic Institute (RPI) and from KNMI. The existing gravimeter recorded an anomalous signal prior to the onset of eruptive activity at Kīlauea in late December 2021, but it is difficult to interpret data recorded by a single station. Data from the new network should provide a better understanding of subsurface magma movement associated with intrusions and eruptions at Kīlauea.
Sources/Usage: Public Domain. View Media Details
Kīlauea Gravity Survey - April 2022
Over several weeks in April, USGS Hawaiian Volcano Observatory scientists, along with visiting scientist from other volcano observatories, conducted the annual Kīlauea microgravity survey.
Over several weeks in April, USGS Hawaiian Volcano Observatory scientists, along with visiting scientist from other volcano observatories, conducted the annual Kīlauea microgravity survey.
Continuous gravimeter
A continuous gravimeter in an enclosure designed by Hawaiian Volcano Observatory staff. USGS image.
A continuous gravimeter in an enclosure designed by Hawaiian Volcano Observatory staff. USGS image.
Campaign gravity measurement
A campaign gravity measurement being made near Keanakākoʻi Crater, within Hawaiʻi Volcanoes National Park. Kīlauea's summit eruption plume and Mauna Loa are visible in the background. USGS image.
A campaign gravity measurement being made near Keanakākoʻi Crater, within Hawaiʻi Volcanoes National Park. Kīlauea's summit eruption plume and Mauna Loa are visible in the background. USGS image.
Hawaiian Volcano Observatory continuous gravimeter station on Kīlauea
A Hawaiian Volcano Observatory continuous gravimeter station on Kīlauea Volcano. The continuous gravimeter is located within the weather-proof enclosure in the foreground of the photograph. Power systems for the gravimeter and continuous GPS are visible in the center of the photograph and consist of solar panels and batteries in weather-proof enclosures.
A Hawaiian Volcano Observatory continuous gravimeter station on Kīlauea Volcano. The continuous gravimeter is located within the weather-proof enclosure in the foreground of the photograph. Power systems for the gravimeter and continuous GPS are visible in the center of the photograph and consist of solar panels and batteries in weather-proof enclosures.