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Graphic depicting a lahar coming off a volcano on a sunny day and people evacuating to high ground.
Lahar Safety Infographic
Lahar Safety Infographic
Graphic depicting a lahar coming off a volcano on a sunny day and people evacuating to high ground.

Lahar Safety Infographic

Lahar Safety Infographic

A lahar is a volcanic mudflow. Learn if you are if you are in a lahar hazard zone and how to evacuate to high ground. If you are in a lahar hazard zone and get a lahar alert - go now! Every second matters. 

By
Natural Hazards Mission Area, Volcano Hazards Program, California Volcano Observatory, Cascades Volcano Observatory
Graphic depicting a lahar coming off a volcano on a sunny day and people evacuating to high ground.

Lahar Safety Infographic

Lahar Safety Infographic

A lahar is a volcanic mudflow. Learn if you are if you are in a lahar hazard zone and how to evacuate to high ground. If you are in a lahar hazard zone and get a lahar alert - go now! Every second matters. 

By
Natural Hazards Mission Area, Volcano Hazards Program, California Volcano Observatory, Cascades Volcano Observatory
This photograph shows a model volcano sitting on a table surrounded by people. The model volcano has a plume of fine material suspended in the air above it, indicating it erupted immediately before the photo was taken. In front of the table, children participants face away from the camera looking at the volcano and the plume. Behind the table, animated scientists in brightly colored shirts are smiling and looking up at the plume.
2026 Pacific Islanders Encouraging Fun, Science & Technology (PIEFEST) in San Mateo, CA
2026 Pacific Islanders Encouraging Fun, Science & Technology (PIEFEST) in San Mateo, CA
This photograph shows a model volcano sitting on a table surrounded by people. The model volcano has a plume of fine material suspended in the air above it, indicating it erupted immediately before the photo was taken. In front of the table, children participants face away from the camera looking at the volcano and the plume. Behind the table, animated scientists in brightly colored shirts are smiling and looking up at the plume.

2026 Pacific Islanders Encouraging Fun, Science & Technology (PIEFEST) in San Mateo, CA

2026 Pacific Islanders Encouraging Fun, Science & Technology (PIEFEST) in San Mateo, CA

An eruption of the tabletop "Mount Shasta" using cornstarch as volcanic ash and puffed rice cereal as "lava bombs". USGS photo by M. Glasgow.

By
California Volcano Observatory
This photograph shows a model volcano sitting on a table surrounded by people. The model volcano has a plume of fine material suspended in the air above it, indicating it erupted immediately before the photo was taken. In front of the table, children participants face away from the camera looking at the volcano and the plume. Behind the table, animated scientists in brightly colored shirts are smiling and looking up at the plume.

2026 Pacific Islanders Encouraging Fun, Science & Technology (PIEFEST) in San Mateo, CA

2026 Pacific Islanders Encouraging Fun, Science & Technology (PIEFEST) in San Mateo, CA

An eruption of the tabletop "Mount Shasta" using cornstarch as volcanic ash and puffed rice cereal as "lava bombs". USGS photo by M. Glasgow.

By
California Volcano Observatory
This photo shows a science festival booth surrounded by children and their families. A model volcano sits on a blue tarp behind a "Mt Shasta Rocks!" sign. Behind the table, a scientist in an orange USGS cap explains volcanic rocks, while another scientist in a volcano-themed Hawaiian shirt prepares the model volcano for its next "eruption".
USGS California Volcano Observatory outreach at a Bay Area science festival
USGS California Volcano Observatory outreach at a Bay Area science festival
This photo shows a science festival booth surrounded by children and their families. A model volcano sits on a blue tarp behind a "Mt Shasta Rocks!" sign. Behind the table, a scientist in an orange USGS cap explains volcanic rocks, while another scientist in a volcano-themed Hawaiian shirt prepares the model volcano for its next "eruption".

USGS California Volcano Observatory outreach at a Bay Area science festival

USGS California Volcano Observatory outreach at a Bay Area science festival

CalVO scientists explaining the differences between lava types to several future volcanologists while "Mount Shasta" prepares for its next eruption. USGS photo by J. Ball

By
California Volcano Observatory
This photo shows a science festival booth surrounded by children and their families. A model volcano sits on a blue tarp behind a "Mt Shasta Rocks!" sign. Behind the table, a scientist in an orange USGS cap explains volcanic rocks, while another scientist in a volcano-themed Hawaiian shirt prepares the model volcano for its next "eruption".

USGS California Volcano Observatory outreach at a Bay Area science festival

USGS California Volcano Observatory outreach at a Bay Area science festival

CalVO scientists explaining the differences between lava types to several future volcanologists while "Mount Shasta" prepares for its next eruption. USGS photo by J. Ball

By
California Volcano Observatory
A simplified set of plots of earthquake sequences, with magnitude on the vertical and time on the horizontal axis. In the top plot, dots show earthquake magnitude starting off large and getting smaller and less frequent over time. On the bottom plot, earthquake magnitudes and times don't follow any particular pattern but happen in bursts.
Types of earthquake sequences
Types of earthquake sequences
A simplified set of plots of earthquake sequences, with magnitude on the vertical and time on the horizontal axis. In the top plot, dots show earthquake magnitude starting off large and getting smaller and less frequent over time. On the bottom plot, earthquake magnitudes and times don't follow any particular pattern but happen in bursts.

Types of earthquake sequences

Types of earthquake sequences

These simplified plots of earthquake magnitude versus time show the differences between tectonic earthquake sequences and magmatic earthquake swarms. Figure by Alicia Hotovec-Ellis, USGS.

By
California Volcano Observatory
A simplified set of plots of earthquake sequences, with magnitude on the vertical and time on the horizontal axis. In the top plot, dots show earthquake magnitude starting off large and getting smaller and less frequent over time. On the bottom plot, earthquake magnitudes and times don't follow any particular pattern but happen in bursts.

Types of earthquake sequences

Types of earthquake sequences

These simplified plots of earthquake magnitude versus time show the differences between tectonic earthquake sequences and magmatic earthquake swarms. Figure by Alicia Hotovec-Ellis, USGS.

By
California Volcano Observatory
An oblique Google Earth map of the San Francisco Bay area, looking north from the Santa Cruz mountains. Major cities, active tectonic faults, and the location of the San Ramon earthquake swarm are highlighted. The Clear Lake Volcanic Field, Mount Shasta, and the Berkeley Hills volcanics are also annotated to show that the San Ramon earthquake swarm is not happening near any active volcanoes.
Map of the January-February 2026 San Ramon earthquake swarm, Bay area faults, and volcanic areas
Map of the January-February 2026 San Ramon earthquake swarm, Bay area faults, and volcanic areas
An oblique Google Earth map of the San Francisco Bay area, looking north from the Santa Cruz mountains. Major cities, active tectonic faults, and the location of the San Ramon earthquake swarm are highlighted. The Clear Lake Volcanic Field, Mount Shasta, and the Berkeley Hills volcanics are also annotated to show that the San Ramon earthquake swarm is not happening near any active volcanoes.

Map of the January-February 2026 San Ramon earthquake swarm, Bay area faults, and volcanic areas

Map of the January-February 2026 San Ramon earthquake swarm, Bay area faults, and volcanic areas

This oblique Google Earth map shows the location of the 2026 San Ramon earthquake swarm, along with notable faults in the San Francisco Bay area and the nearest volcanic areas to the swarm. Google Earth image modified by J. Ball, USGS.

By
California Volcano Observatory
An oblique Google Earth map of the San Francisco Bay area, looking north from the Santa Cruz mountains. Major cities, active tectonic faults, and the location of the San Ramon earthquake swarm are highlighted. The Clear Lake Volcanic Field, Mount Shasta, and the Berkeley Hills volcanics are also annotated to show that the San Ramon earthquake swarm is not happening near any active volcanoes.

Map of the January-February 2026 San Ramon earthquake swarm, Bay area faults, and volcanic areas

Map of the January-February 2026 San Ramon earthquake swarm, Bay area faults, and volcanic areas

This oblique Google Earth map shows the location of the 2026 San Ramon earthquake swarm, along with notable faults in the San Francisco Bay area and the nearest volcanic areas to the swarm. Google Earth image modified by J. Ball, USGS.

By
California Volcano Observatory
This shaded relief map shows the Long Valley Caldera, Lake Crowley, and the town of Mammoth Lakes. Highway 395 cuts diagonally across the caldera from northwest to southeast. In the center of the map, a label shows the location of GPS station KRAC/KRAK.
Location of GPS (GNSS) station KRAC/KRAK in the Long Valley Caldera
Location of GPS (GNSS) station KRAC/KRAK in the Long Valley Caldera
This shaded relief map shows the Long Valley Caldera, Lake Crowley, and the town of Mammoth Lakes. Highway 395 cuts diagonally across the caldera from northwest to southeast. In the center of the map, a label shows the location of GPS station KRAC/KRAK.

Location of GPS (GNSS) station KRAC/KRAK in the Long Valley Caldera

Location of GPS (GNSS) station KRAC/KRAK in the Long Valley Caldera

The location of GPS station KRAC and its predecessor KRAK, slightly north of the center of deflation in Long Valley. USGS figure by Josh Crozier and Alicia Hotovec-Ellis.

By
California Volcano Observatory, Long Valley Caldera
This shaded relief map shows the Long Valley Caldera, Lake Crowley, and the town of Mammoth Lakes. Highway 395 cuts diagonally across the caldera from northwest to southeast. In the center of the map, a label shows the location of GPS station KRAC/KRAK.

Location of GPS (GNSS) station KRAC/KRAK in the Long Valley Caldera

Location of GPS (GNSS) station KRAC/KRAK in the Long Valley Caldera

The location of GPS station KRAC and its predecessor KRAK, slightly north of the center of deflation in Long Valley. USGS figure by Josh Crozier and Alicia Hotovec-Ellis.

By
California Volcano Observatory, Long Valley Caldera
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