Images

Schematic displaying the general processes associated with collapse of Yellowstone Caldera.  (A) Pre-caldera volcanism includes the eruption of dome complexes from the underlying magma chambers.  (B) The caldera-forming eruption evacuates a significant amount of magma from the chamber, causing the overlying crustal block to subside into the void space.&nbs

In recent weeks, HVO geophysicists have been undertaking a Global Positioning System (GPS) campaign across Kīlauea.

HVO scientists continue their survey of Kīlauea caldera floor, including the down-dropped block, for ​diffuse volcanic gas emissions. This photo shows a large crack, on a portion of the caldera floor that subsided in 2018, that is emitting volcanic gas and steam.

Stacked lava flows are visible in the wall of the down-dropped block, which was exposed during the Kīlauea summit collapse events in 2018. A small exposure of lighter-colored volcanic ash, likely the Keanakāko‘i tephra deposits erupted during Kīlauea's last explosive phase several hundred years ago, is visible beneath tens of meters (yards) of lava flows.

Over the past few months, HVO geophysicists have been conducting the annual high-precision Global Positioning System (GPS) survey of Kīlauea. The annual survey supplements HVO's continuous GPS monitoring stations and provides information on vertical and horizontal deformation of the ground surface.

Typical exposure of tabular blocks of layered ash in a matrix of cross-bedded ash. The tabular blocks were deposited, rapidly hardened, and ripped up and transported downstream along the ancestral Missouri River system with another pulse of ash and water, forming the cross-bedded matrix.

A view looking north into Halema‘uma‘u on July 30, 2021. Although eruptive activity has paused at the summit of Kīlauea, HVO geologists still monitor the lava lake and summit area weekly. Lava lake surface depths remain the same since mid to late May when active lava was last observed at the surface. USGS photo by N. Deligne. 

Eruptive activity paused within Halema‘uma‘u, at Kīlauea's summit, a bit more than 2 months ago. In that time, the spatter cone at the western fissure complex has slowly degraded due to numerous small scale collapses, leaving a debris apron (fresh looking rubble) and exposing the interior of the spatter cone. USGS photo by N. Deligne.

A USGS scientist calibrates two MultiGas instruments to prepare for mapping volcanic gasses on the floor of Kīlauea caldera. With the MultiGas strapped to metal backpack frames, the scientists traverse across the caldera floor to collect gas data which will be compared to the last survey.

While mapping volcanic gasses in Kīlauea caldera, HVO scientists got a view (looking west) of Halema‘uma‘u and the down-dropped block. The steep crater walls of Halema‘uma‘u are visible in the upper center and right portions of this photo, but the recently active lava lake is out of view below the eastern crater rim.

HVO geologists measure the depth to the water table at the Keller Well, located south of Halema‘uma‘u crater. The Keller Well is a borehole drilled in 1973 to a depth of 4,140 ft (1,262 m) that has been used to monitor the hydrology of the summit region of Kīlauea volcano. Photo taken on July 27, 2021, at 9:30 a.m. HST. USGS photo by J.M. Chang.

An HVO geologist conducts maintenance on the S1cam web camera located along the southern rim of Halema‘uma‘u, at the summit of Kīlauea.

The Yellowstone borehole geophysical network, installed by UNAVCO in 2007–2008. The placement of the boreholes is focused primarily around the caldera, and the boreholes contain a mix of instruments, including strainmeters, seismometers, tiltmeters, and pore pressure sensors.

HVO scientists walk transects along the down-dropped portion of Kīlauea caldera floor as part of a gas survey conducted on July 22.

An HVO scientist samples the gas around a crack identified as emitting elevated levels of carbon dioxide (a volcanic gas) on the down-dropped block within Kīlauea caldera. The sample will later be analyzed to determine its complete chemical composition. This work was conducted within a closed area of Hawai‘i Volcanoes National Park, with park permission.

An HVO geologist conducts a routine high-precision survey of the inactive lava lake in Halema‘uma‘u, at the summit of Kīlauea volcano. Mist moving across the caldera on the morning of July 22 produced a rainbow over the lake. No significant changes have occurred in Halema‘uma‘u in recent weeks. USGS photo by M. Patrick.

This aerial photo of the inactive lava lake within Halema‘uma‘u at the summit of Kīlauea was captured during a routine helicopter overflight by HVO geologists on Thursday, July 22, 2021.

This wide-angle aerial view looks southeast over Kīlauea's summit caldera, with the recently active lava lake in Halema‘uma‘u visible in the lower right. On the left side of the photo, the large cliffs formed during the 2018 collapses are visible. Kīlauea Iki can be seen in the upper left. USGS photo by M. Patrick, taken on July 22, 2021.

On July 22, HVO scientists surveyed the floor of the down-dropped block within Kīlauea caldera for ​diffuse volcanic gas emissions. This particular part of the caldera floor subsided during Kīlauea's collapse events in 2018.

Visible and thermal infrared images of Yellowstone acquired on July 17, 2021.  In the visible image, Landsat 8 channels 4-3-2 are assigned red-green-blue colors (respectively) to simulate natural color.  In thermal infrared image, bright pixels are warmer, and dark pixels are cooler.  The full satellite images are clipped to the boundaries of Yellowst

Seismogram from station YTP in Yellowstone National Park showing earthquakes from the swarm beneath Yellowstone Lake that began late on July 15, 2021. Each row represents 30 minutes of seismic data.