This map shows the location of the June 24, 2024 earthquake swarm at the Lassen Volcanic Center relative to Lassen Peak and Growler & Morgan Hot Springs. Earthquakes are indicated by white, blue, and yellow circles, scaled to the earthquake size.
Images
![Shaded relief map showing Lassen Volcanic National Park, with Lassen Peak labeled in the northern portion of the map, Growler & Morgan hot springs to the southwest, and the June 24 2024 swarm to the southeast](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/media/images/lassen%20swarm%202024-06-24%20map.png?itok=unjAnrF3)
This map shows the location of the June 24, 2024 earthquake swarm at the Lassen Volcanic Center relative to Lassen Peak and Growler & Morgan Hot Springs. Earthquakes are indicated by white, blue, and yellow circles, scaled to the earthquake size.
![Helicorder record showing dozens of tiny earthquake traces occurring over 12 hours, with each line comprising 15 minutes and earthquakes looking like drum cymbals turned on their sides.](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/media/images/lassen_LSIB_helicorder.png?itok=Lr0RzNsX)
This digital helicorder record from station LSIB on the Northern California Seismic Network emphasizes the dozens of tiny earthquakes in Lassen's June 24 swarm. Earch line of the helicorder shows 15 minutes of time, with the entire record covering 24 hours.
This digital helicorder record from station LSIB on the Northern California Seismic Network emphasizes the dozens of tiny earthquakes in Lassen's June 24 swarm. Earch line of the helicorder shows 15 minutes of time, with the entire record covering 24 hours.
![Microscopic view of different groundmass textures in rocks](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/media/images/groundmass_figure.png?itok=vWKb6AXW)
Microscopic view of different groundmass textures in rocks. On the left, this groundmass is a good choice for argon dating, as it consists of abundant interconnected crystals. On the right, the groundmass consists predominantly of glass (black because it does not transmit cross-polarized light) and is a poor choice for argon dating.
Microscopic view of different groundmass textures in rocks. On the left, this groundmass is a good choice for argon dating, as it consists of abundant interconnected crystals. On the right, the groundmass consists predominantly of glass (black because it does not transmit cross-polarized light) and is a poor choice for argon dating.
![Mass spectrometer, used to measure the ration of atoms with different masses, in the USGS laboratory at Moffett Field, California](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/media/images/mass_spec_figure.png?itok=pajtf6zf)
Mass spectrometer, used to measure the ration of atoms with different masses, in the USGS laboratory at Moffett Field, California
linkA mass spectrometer is used to measure the ratio of atoms with different masses—in this case, the different isotopes of argon gas, which can be used to determine the age of a volcanic rock. Left: a side view of a mass spectrometer at the USGS Argon Geochronology Laboratory in Moffett Field, CA. Right: a close-up view of the sample chamber in this mass spectrometer.
Mass spectrometer, used to measure the ration of atoms with different masses, in the USGS laboratory at Moffett Field, California
linkA mass spectrometer is used to measure the ratio of atoms with different masses—in this case, the different isotopes of argon gas, which can be used to determine the age of a volcanic rock. Left: a side view of a mass spectrometer at the USGS Argon Geochronology Laboratory in Moffett Field, CA. Right: a close-up view of the sample chamber in this mass spectrometer.
![A geologist crouches next to a rhyolite outcrop and points to an egg-shaped mass of radiating pink minerals about the size of a cantaloupe. The rest of the rock is pocked with other egg to grapefruit sized pink crystal masses, interspersed with chunky fragments of black glassy lava.](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/media/images/DSC_1753.png?itok=lqn2pT3N)
The presence of spherulites indicates that a lava flow cooled quickly, and their mineralogy holds clues to its precise cooling history. USGS photo by Jessica Ball
The presence of spherulites indicates that a lava flow cooled quickly, and their mineralogy holds clues to its precise cooling history. USGS photo by Jessica Ball
![A broad, flat plain covered in dull green sagebrush stretches away from the viewer in this panorama. The photo is being taken from a rocky hill, with snow-capped, sharp peaks on the far side of the plain and low raised hills on the right side of the photo. One geologist is sitting on the rocks at lower right and one geologist is standing and giving a peace sign.](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/media/images/PXL_20230831_192734283.PANO_.png?itok=eXgiOQLI)
This panorama of the Long Valley Caldera, looking from north to south, shows its broad central plain, post-caldera rhyolite flows and uplift on the right, and eastern Sierra Nevada in the background. USGS photo by Jessica Ball.
This panorama of the Long Valley Caldera, looking from north to south, shows its broad central plain, post-caldera rhyolite flows and uplift on the right, and eastern Sierra Nevada in the background. USGS photo by Jessica Ball.
Kyle R. Anderson is a Volcano Geophysicist who works at the USGS California Volcano Observatory.
Kyle R. Anderson is a Volcano Geophysicist who works at the USGS California Volcano Observatory.
Phil Dawson, a Volcano Seismologist with the California Volcano Observatory, stands next to a volcanic rock on the flank of Mount Shasta, California.
Phil Dawson, a Volcano Seismologist with the California Volcano Observatory, stands next to a volcanic rock on the flank of Mount Shasta, California.
Joshua Crozier is a Mendenhall Postdoctoral Fellow working at the USGS California Volcano Observatory
Joshua Crozier is a Mendenhall Postdoctoral Fellow working at the USGS California Volcano Observatory
![A steaming hot spring and stream flow through the yellow-and-white altered rock of a hydrothermal area. A raised walkway is visible in the background.](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/media/images/Bergfeld_DevilsKitchen_03_0.jpg?itok=FwU0-nV1)
Devils Kitchen in the Lassen Volcanic Region (within the bounds of the Lassen Volcanic National Park) is the second largest of Lassen's hydrothermal areas, after Bumpass Hell. Located in the Warner Valley in the southeast corner of the Park, Devils Kitchen contains boiling springs, mudpots, hot streams, and steam vents. USGS photo courtesy of Deb Bergfeld
Devils Kitchen in the Lassen Volcanic Region (within the bounds of the Lassen Volcanic National Park) is the second largest of Lassen's hydrothermal areas, after Bumpass Hell. Located in the Warner Valley in the southeast corner of the Park, Devils Kitchen contains boiling springs, mudpots, hot streams, and steam vents. USGS photo courtesy of Deb Bergfeld
Andy Calvert and Tony Pivarunas drill into the face of a lava flow on Ash Creek Butte, a Pleistocene shield volcano northeast of Mount Shasta. USGS photo by Dawnika Blatter
Andy Calvert and Tony Pivarunas drill into the face of a lava flow on Ash Creek Butte, a Pleistocene shield volcano northeast of Mount Shasta. USGS photo by Dawnika Blatter
USGS-Cascades Volcano Observatory geophysicist Rebecca Kramer works on station PR05, which is part of the Mount Rainier lahar detection network (Mount Rainier is pictured in the distance). The purpose of the site visit was to upgrade the power system and deploy infrasound equipment.
USGS-Cascades Volcano Observatory geophysicist Rebecca Kramer works on station PR05, which is part of the Mount Rainier lahar detection network (Mount Rainier is pictured in the distance). The purpose of the site visit was to upgrade the power system and deploy infrasound equipment.
Rhyolite lavas in the Yellowstone Caldera younger than 631,000 years
Rhyolite lavas in the Yellowstone Caldera younger than 631,000 years
![Mount Konocti as seen from the town of Clear Lake.](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/thumbnails/image/Mt.%20Konocti%20from%20city%20of%20Clearlake.jpg?itok=5GIm25ku)
Mount Konocti as seen from the town of Clear Lake.
Mount Konocti as seen from the town of Clear Lake.
![Thurston Lake and Mount Konocti, Clear Lake Volcanic Field](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/thumbnails/image/Thurston%20L%20and%20Mt.%20Konocti.jpg?itok=PTnukfex)
Thurston Lake and Mount Konocti, Clear Lake Volcanic Field, California.
Thurston Lake and Mount Konocti, Clear Lake Volcanic Field, California.
View of the Mammoth Mountain lava dome complex overlooking Horseshoe Lake.
View of the Mammoth Mountain lava dome complex overlooking Horseshoe Lake.
Photograph of permanent eddy covariance station installed since 2014 in area of volcanic CO2 emissions on Mammoth Mountain, California. USGS photo by Jennifer Lewicki, August 2019.
Photograph of permanent eddy covariance station installed since 2014 in area of volcanic CO2 emissions on Mammoth Mountain, California. USGS photo by Jennifer Lewicki, August 2019.
A 3-4m (10-12 ft) high outcrop of basalt lava, part of a broader lava flow. These flows were erupted about 300,000 years ago following basalt dike intrusions in a rear-arc region of northern California. The eruptions of three of these flows are thought to have taken place within several hundred years of each other.
A 3-4m (10-12 ft) high outcrop of basalt lava, part of a broader lava flow. These flows were erupted about 300,000 years ago following basalt dike intrusions in a rear-arc region of northern California. The eruptions of three of these flows are thought to have taken place within several hundred years of each other.
![A two part figure with a shaded-relief map view of the Long Valley Caldera marked with the outlines of its resurgent dome, Mammoth Mountain, Crowley Lake, the caldera outline, and major roads. Below is a west-to-east cross-section cartoon of the caldera, showing the locations of these features as well as the depth of caldera fill, basement rocks, and the paths of cold and hot water near magmatic intrusions.](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/media/images/longvalley_hotwater_factsheetfig-01.png?itok=ERqhOVNt)
Simplified geologic map (left) and diagrammatic cross section (right) of Long Valley Caldera. The resurgent dome, Doe Ridge, Mammoth Mountain, and the Inyo Craters and Domes all reflect volcanic activity since 760,000 years ago, when a giant eruption formed the caldera.
Simplified geologic map (left) and diagrammatic cross section (right) of Long Valley Caldera. The resurgent dome, Doe Ridge, Mammoth Mountain, and the Inyo Craters and Domes all reflect volcanic activity since 760,000 years ago, when a giant eruption formed the caldera.
![Brown landscape with volcano in the background](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/thumbnails/image/VW-2017-01-19_CalVO_USGS.jpg?itok=rpbdzaKP)
Mount Shasta, a steep-sided Cascade Range stratovolcano in Northern California, looms above Little Glass Mountain, a thick obsidian flow erupted from the Medicine Lake shield volcano about 1,000 years ago. These are just two of the young volcanic areas monitored by the USGS California Volcano Observatory. USGS photo.
Mount Shasta, a steep-sided Cascade Range stratovolcano in Northern California, looms above Little Glass Mountain, a thick obsidian flow erupted from the Medicine Lake shield volcano about 1,000 years ago. These are just two of the young volcanic areas monitored by the USGS California Volcano Observatory. USGS photo.
![High-resolution, bare-earth, airborne light detection and ranging (...](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/vhp_img5987.png?itok=hdNUV_Vj)
High-resolution, bare-earth, airborne light detection and ranging (LiDAR) image, looking obliquely northwest into Rocky Ridge.
High-resolution, bare-earth, airborne light detection and ranging (LiDAR) image, looking obliquely northwest into Rocky Ridge.