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.
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Lassen Volcanic Center earthquake swarm of June 24, 2024
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.
LSIB helicorder trace from the Lassen Volcanic Center on June 24, 2024.
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
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
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.
Large spherulites in Hot Creek rhyolite lava in the Long Valley Caldera
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
Panoramic view of the Long Valley Caldera from its north side
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.