Images

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.

Non-volcanic peaks of the North Cascades lie in the background. Dusty Creek drainage experiences regular lahars. Gamma Ridge Formation are hydrothermally altered rocks on left ridge. Loose pyroclastic fill deposits cap right ridge; Eastern view, Glacier Peak, Washington.

Mount Adams viewed from the southeast in Klickitat Valley, Washington.

Lahar deposit cross section in the Trout Lake lowland, which originated from Mount Adams. Thickness of deposit is about 2.5 m (8 ft).

Quaternary volcanic rocks are shown in black, and main centers are labeled. Chilliwack batholith and Pemberton belt represent Oligocene– Miocene arc 20–50 km inboard of Quaternary Garibaldi arc. Dashed line surrounding Puget Lowland shows maximum extent of Puget lobe of Cordilleran Ice Sheet during the last glaciation.

Mount Baker's crater lake in 1976 formed due to glacial and snow melt as a result of increased heat from magma beneath the surface. Fumarole on left ejecting gas at a velocity of 268 kph (167 mph).

This notice was posted at campgrounds around Baker Lake by the US Forest Service in June 1975. Normally, Baker Reservoir approaches capacity during mid-summer. At most other times, reservoir levels are low enough to impound lahars the size of those that occurred in 1843.

No date exists for this photograph, but the image is likely circa 1900. Note the postcard copyright date of 1903.

Seismogram signal examples from volcanic earthquakes: volcano tectonic (VT) Low Frequency (LF)/Deep Long-Period (DLP), hybrid (mix of VT and LF), very low frequency (VLF), and Tremor.

Boulder Creek leading from Mount Baker, Washington is a hydrology monitoring site where water is collected and measured for chemicals that may signal volcanic unrest.

Sampling gas and taking temperature measurements from a fumarole at the summit of Mount Rainier, Washington.

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.

Haleakalā Volcano map showing strata of the HANA Volcanics by age.

Aerial view of Haleakalā Crater northward to Ko‘olau Gap. Sharp rimmed crater in near ground is Ka Lu‘u o ka ‘Ō‘ō.

Distribution of young volcanic rocks by age in Haleakalā Crater, Maui.

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).

Volcano Evacuation Route sign along a roadway in Washington State.

Map Showing Outbreak Progression In 1956

Impressive columns like these form along the margins of ice-confined lava flows but usually are eroded off the sides due to continued glacial movement after an eruption ceases. Columns are better preserved at the ends of the flows (this photo) where they are protected somewhat from the ice.

Although numerous intensity scales have been developed over the last several hundred years to evaluate the effects of earthquakes, the one currently used in the United States is the Modified Mercalli Intensity (MMI) Scale. It was developed in 1931 by the American seismologists Harry Wood and Frank Neumann.

Geologic Hazards at Volcanoes (click for larger version)