Images

Vectors indicate Pacific Plate motion relative to presumed fixed mantle hot spot in millimeters per year. Gray lines indicate fracture zones. Isochrons along the Emperor Seamounts chain show the age of volcanism in millions of years. Ocean floor ages from imagery available on EarthByte.

Mount Adams elevation is 3,745 m (12, 286 ft). Mount St. Helens was the smallest of five major volcanic peaks in Washington State.

Family Emergency Preparedness Plan

Geothermal ice cave at Mount Baker's summit formed by melting of a glacier due to increased heat from subsurface magma and fumarole on the surface expelling hot gasses.

Mount Hood dominates the skyline outside of Portland, Oregon on a clear day. An major eruption of Mount Hood would pose a great hazard to the regional economy.

Mount Hood in the not-so-far distance beyond Downtown Portland, Oregon. Photograph taken at the top of the Portland Aerial Tram line on Marquam Hill.

Mount Bachelor viewed from the south. Sparks Lake and South Sister visible in the background. Oregon.

Mount Bachelor's east facing ski slopes at sunrise.

Visible relief in the hillside exposure is about 800-900 ft. Dusty assemblage deposit occurred approximately between 5100 and 5500 yr B.P. Magma volume of >5 km3, which is a lot for what was probably one eruptive stage. The source lava dome is gone, apparently having disintegrated entirely during extrusion and subsequent glacial interaction.

Glacier Peak volcano, Washington reflected in pond below the Whitechuck Glacier, view from the south in late summer.

Hualālai Volcano (center) above Kīholo Bay on Hawai‘i Island's West Coast is flanked by lava flow erupted from the volcano around 1800 (right) and 1859 Mauna Loa flow (left).

CalVO scientist Tom Sisson studies a lava flow in the Harrat Rahat Volcanic Field in Saudi Arabia for an international collaboration with the Saudi Geological Survey to conduct a seismic and volcanic hazard assessment for the volcanic field.

Simulated fractures and subsidence above a widening dike (dark area at bottom) were generated in a small-scale model using a box filled with flour, sugar, and corn meal. The simulated dike (tip is dark area bottom center of photograph) consisted of two linoleum sheets taped together.

CalVO staff assembled in the Rambo Auditorium, Menlo Park, CA

Guardian Geyser and Norris Geyser Basin, Yellowstone National Park.

Locations (Lat, Long, Depth) of January 17, 2010, earthquake swarm on Madison Plateau, Yellowstone National Park.

Tiltmeters allowed 24-hour monitoring as the information was telemetered back to CVO. Other instruments such as displacement meters for measuring cracks, seismometers for measuring earthquakes, gas sensors for measuring gas concentrations, and magnetometers for measuring the magnetic field, were also used for 24-hour monitoring.

Mammoth Hot Springs at Yellowstone National Park, Wyoming.

Magma forms above the subducting slab of oceanic crust and accumulates at the base of Earth's rigid crust before collecting in a storage zone 13 km (8 mi) beneath the volcano prior to eruption.

South Sister northwest flank. Right shoulder at skyline is thin sheet of mafic material from 22ka summit eruption. Red cinders in headwall cirques are layered with dipping lava flows.

Geologic Map of Three Sisters Volcanic Cluster, Cascade Range, Oregon