Distribution of hydrothermal features in Yellowstone as a function of their pH (modified and updated from Nordstrom et al., 2009). There are two distinct groupings: one is more acidic, and the other neutral to basic.
Images
![Distribution of hydrothermal features in Yellowstone as a function of their pH](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/media/images/pH%20abundance%20figure.jpg?itok=dgBPflgL)
Distribution of hydrothermal features in Yellowstone as a function of their pH (modified and updated from Nordstrom et al., 2009). There are two distinct groupings: one is more acidic, and the other neutral to basic.
![Color photograph of scientist with netting](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/media/images/MicrosoftTeams-image%20%2831%29_0.png?itok=OxmSnWIp)
An HVO scientist prepares netting to move a pallet of equipment via helicopter for the Kīlauea Seismic Imaging Project on April 28, 2023. During the project, caches of equipment are deployed around Kīlauea summit. HVO scientists and collaborators then distribute the equipment from the cache into a network across the summit region. USGS image by M. Patrick.
An HVO scientist prepares netting to move a pallet of equipment via helicopter for the Kīlauea Seismic Imaging Project on April 28, 2023. During the project, caches of equipment are deployed around Kīlauea summit. HVO scientists and collaborators then distribute the equipment from the cache into a network across the summit region. USGS image by M. Patrick.
![Color photograph pallet of equipment](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/media/images/MicrosoftTeams-image%20%2829%29_1.png?itok=V5Br2bv0)
A pallet of buckets containing equipment for the Kīlauea Seismic Imaging Project is placed on netting so that it can be moved via helicopter sling load. These pallets package a small portion of the 1,800 seismic nodes (small earthquake-detecting devices) that are being deployed in Kīlauea summit region as part of the project.
A pallet of buckets containing equipment for the Kīlauea Seismic Imaging Project is placed on netting so that it can be moved via helicopter sling load. These pallets package a small portion of the 1,800 seismic nodes (small earthquake-detecting devices) that are being deployed in Kīlauea summit region as part of the project.
![Color photograph pallet of equipment](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/media/images/MicrosoftTeams-image%20%2832%29_1.png?itok=nV1urJoe)
The gear for the Kīlauea Seismic Imaging Project is staged and ready to be moved on Crater Rim Drive in the closed area of Hawai‘i Volcanoes National Park. Portions of Crater Rim Drive collapsed into Kīlauea caldera in 2018 and this project is partially funded by the Additional Supplemental Appropriations for Disaster Relief Act of 2019 (H.R.
The gear for the Kīlauea Seismic Imaging Project is staged and ready to be moved on Crater Rim Drive in the closed area of Hawai‘i Volcanoes National Park. Portions of Crater Rim Drive collapsed into Kīlauea caldera in 2018 and this project is partially funded by the Additional Supplemental Appropriations for Disaster Relief Act of 2019 (H.R.
![Color photograph of steaming crater and sunrise](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/media/images/multimediaFile-3856.jpg?itok=9Awk4DNd)
Early in the morning on Friday, April 21, two crews of geologists from the Hawaiian Volcano Observatory flew via helicopter into Halema‘uma‘u crater at the summit of Kīlauea to collect geologic samples.
Early in the morning on Friday, April 21, two crews of geologists from the Hawaiian Volcano Observatory flew via helicopter into Halema‘uma‘u crater at the summit of Kīlauea to collect geologic samples.
![Color photograph of crater wall](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/media/images/multimediaFile-3857_0.jpg?itok=fO8WAn_S)
April 21, 2023 — Geologist surveys newly exposed lavas and tephra in the wall of Kīlauea caldera
linkHawaiian Volcano Observatory geologists documented newly exposed lava flows and tephra layers in the northwest wall of Kīlauea caldera during a field visit the morning of April 21, 2023.
April 21, 2023 — Geologist surveys newly exposed lavas and tephra in the wall of Kīlauea caldera
linkHawaiian Volcano Observatory geologists documented newly exposed lava flows and tephra layers in the northwest wall of Kīlauea caldera during a field visit the morning of April 21, 2023.
![Color photograph of crater wall](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/media/images/multimediaFile-3853_0.jpg?itok=njLzZ9yD)
April 21, 2023 — Geologists survey exposed lavas and tephra in the wall of Kaluapele (Kīlauea caldera)
linkThree orange-clad geologists from the Hawaiian Volcano Observatory can be seen in this image (in orange, near center of image). During a visit to Halema‘uma‘u crater the morning of April 21, 2023, the geologists collected tephra samples from the Uēkahuna bluff along the northern wall of Kīlauea's summit caldera.
April 21, 2023 — Geologists survey exposed lavas and tephra in the wall of Kaluapele (Kīlauea caldera)
linkThree orange-clad geologists from the Hawaiian Volcano Observatory can be seen in this image (in orange, near center of image). During a visit to Halema‘uma‘u crater the morning of April 21, 2023, the geologists collected tephra samples from the Uēkahuna bluff along the northern wall of Kīlauea's summit caldera.
![Color photograph of crater floor](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/media/images/multimediaFile-3854_0.jpg?itok=N2H0__kA)
A morning view of the floor of Halema‘uma‘u, captured by Hawaiian Volcano Observatory geologists during a sampling mission on April 21, 2023. Although the volcano was not erupting when this image was taken, a wispy plume can still be seen rising from the crater floor.
A morning view of the floor of Halema‘uma‘u, captured by Hawaiian Volcano Observatory geologists during a sampling mission on April 21, 2023. Although the volcano was not erupting when this image was taken, a wispy plume can still be seen rising from the crater floor.
![Geologist standing on floor of crater](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/media/images/multimediaFile-3855_0.jpg?itok=U1p4Yp4A)
April 21, 2023 — HVO Geologist on the floor of Halema‘uma‘u crater, in Kaluapele (Kīlauea caldera)
linkA geologist from the Hawaiian Volcano Observatory (HVO) selects a sampling site on the floor of Halema‘uma‘u crater during the morning of April 21, 2023. The geologist is standing near the eastern rim of the lava lake that was active in the western portion of Halema‘uma‘u crater during the January–March, 2023, eruption.
April 21, 2023 — HVO Geologist on the floor of Halema‘uma‘u crater, in Kaluapele (Kīlauea caldera)
linkA geologist from the Hawaiian Volcano Observatory (HVO) selects a sampling site on the floor of Halema‘uma‘u crater during the morning of April 21, 2023. The geologist is standing near the eastern rim of the lava lake that was active in the western portion of Halema‘uma‘u crater during the January–March, 2023, eruption.
![Color map of volcano summit and eruption products](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/media/images/Picture1_25.jpg?itok=a434MnMh)
Map of the Mauna Loa 2022 eruptive fissures, shown as red lines. Red shaded area indicates lava flows produced during the eruption, around the fissure vent areas. Solid white line indicates mapped outer caldera boundary. White dotted line indicates inferred outer caldera boundary that is buried by historic Mauna Loa lava flows. Fissures on map were documented by C.
Map of the Mauna Loa 2022 eruptive fissures, shown as red lines. Red shaded area indicates lava flows produced during the eruption, around the fissure vent areas. Solid white line indicates mapped outer caldera boundary. White dotted line indicates inferred outer caldera boundary that is buried by historic Mauna Loa lava flows. Fissures on map were documented by C.
The Hawaiian Volcano Observatory technician team did maintenance on the Hualālai repeater station during the week of April 10, 2023. This photo shows the team walking towards the site, which is an important telemetry hub for Hawaiian Volcano Observatory volcano monitoring data. Mauna Kea and Mauna Loa are visible in the background. USGS image by M. Warren.
The Hawaiian Volcano Observatory technician team did maintenance on the Hualālai repeater station during the week of April 10, 2023. This photo shows the team walking towards the site, which is an important telemetry hub for Hawaiian Volcano Observatory volcano monitoring data. Mauna Kea and Mauna Loa are visible in the background. USGS image by M. Warren.
A Hawaiian Volcano Observatory technician replaces batteries on the Hualālai repeater station. The station, which relays monitoring signals from nearby stations back the observatory, is powered by batteries that store energy generated by solar panels. USGS image by M. Warren.
A Hawaiian Volcano Observatory technician replaces batteries on the Hualālai repeater station. The station, which relays monitoring signals from nearby stations back the observatory, is powered by batteries that store energy generated by solar panels. USGS image by M. Warren.
A Hawaiian Volcano Observatory technician removes the electronics board on the Hualālai repeater station. The electronics board for the station was replaced with a 48-volt system electronics board as part of a station upgrade. USGS image by C. Parcheta.
A Hawaiian Volcano Observatory technician removes the electronics board on the Hualālai repeater station. The electronics board for the station was replaced with a 48-volt system electronics board as part of a station upgrade. USGS image by C. Parcheta.
A Hawaiian Volcano Observatory scientist drills holes to install a new electronics box for the Hualālai repeater station upgrade. USGS image by M. Warren.
A Hawaiian Volcano Observatory scientist drills holes to install a new electronics box for the Hualālai repeater station upgrade. USGS image by M. Warren.
![Color photograph of technician working on station](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/media/images/multimediaFile-3835_0.jpg?itok=PddKCTcF)
During station maintenance at the Hualālai repeater, Hawaiian Volcano Observatory technicians installed a new webcam, the HLcam. This camera is located on Hualālai and provides view of Mauna Loa's northwest flank.
During station maintenance at the Hualālai repeater, Hawaiian Volcano Observatory technicians installed a new webcam, the HLcam. This camera is located on Hualālai and provides view of Mauna Loa's northwest flank.
![Color photograph of technician working on station](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/media/images/multimediaFile-3839_0.jpg?itok=XiKqfNUv)
The lead electronics technician at the Hawaiian Volcano Observatory checks that the new HLcam is transmitting. The HLcam is located on the southeast side of Hualālai and provides views of the northwest flank of Mauna Loa.
The lead electronics technician at the Hawaiian Volcano Observatory checks that the new HLcam is transmitting. The HLcam is located on the southeast side of Hualālai and provides views of the northwest flank of Mauna Loa.
Hawaiian Volcano Observatory technicians work on installing a new electronics box on the Hualālai repeater station as part of a station upgrade in April 2023. USGS image by M. Warren.
Hawaiian Volcano Observatory technicians work on installing a new electronics box on the Hualālai repeater station as part of a station upgrade in April 2023. USGS image by M. Warren.
Hawaiian Volcano Observatory technicians upgraded the Hualālai repeater station to lithium batteries, despite the chilly temperatures on Hualālai. USGS image by M. Warren.
Hawaiian Volcano Observatory technicians upgraded the Hualālai repeater station to lithium batteries, despite the chilly temperatures on Hualālai. USGS image by M. Warren.
Hawaiian Volcano Observatory technicians install new lithium batteries at the Hualālai repeater station. The station is located at an elevation of 2,160 meters (7,090 feet), on the southeast side of Hualālai. USGS image by M. Warren.
Hawaiian Volcano Observatory technicians install new lithium batteries at the Hualālai repeater station. The station is located at an elevation of 2,160 meters (7,090 feet), on the southeast side of Hualālai. USGS image by M. Warren.
During the week of April 10, Hawaiian Volcano Observatory technicians upgraded the Hualālai repeater site, which is an important telemetry hub for volcano monitoring data. The site is located on the southeast side of Hualālai, at an elevation of 2,160 meters (7,090 feet) above sea level.
During the week of April 10, Hawaiian Volcano Observatory technicians upgraded the Hualālai repeater site, which is an important telemetry hub for volcano monitoring data. The site is located on the southeast side of Hualālai, at an elevation of 2,160 meters (7,090 feet) above sea level.
Simplified map of the Wyoming Province—a craton composed of Archean-age continental crust. Archean- and Proterozoic-age rocks outcrop in many places within the Wyoming Province and are shown as dark grey blobs. The yellow blob highlights the location of the Hellroaring and Crevice plutons, a small portion of which are exposed in northern Yellowstone National Park.
Simplified map of the Wyoming Province—a craton composed of Archean-age continental crust. Archean- and Proterozoic-age rocks outcrop in many places within the Wyoming Province and are shown as dark grey blobs. The yellow blob highlights the location of the Hellroaring and Crevice plutons, a small portion of which are exposed in northern Yellowstone National Park.