Images

Glacier Peak, Washington simplified hazards map showing potential impact area for ground-based hazards during a volcanic event.

Map showing one-year probability of accumulation of 1 centimeter (0.4 inch) or more of tephra from eruptions of volcanoes in the Cascade Range.

Glacier Peak volcano viewed from the west, Washington.

The orange layer just below geologist's hiking pole is the Mazama ash (about 7700 ybp). Below that are glacial deposits. Above the Mazama is about a meter consisting mostly of fine-grained tephras from Glacier Peak, capped by soil and plants. That the tephras sit directly on top of the Mazama indicates that "Dusty" eruptions commenced about 7,000 years ago.

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.

Eruptions in the Cascade Range during the past 4000 years. USGS GIP 64

Glacier Peak volcano, Washington, viewed from the east.

Glacier Peak volcano, Washington, viewed from the east.

Glacier Peak volcano, Washington, viewed from the east.

Summit of Glacier Peak, Washington, view toward the east.

Glacier Peak is the tallest peak amongst a sea of many mountains in northern Washington.

Upper west face of Glacier Peak, Washington.

Upper slopes of Glacier Peak, Washington.

Glacier Peak, Washington, in the prime of summer when much of the snow has melted from its flanks.

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.

Exposed rock ridges are thick Pleistocene lava flows that were confined between large glaciers. Glacier Peak, Washington, view north.

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

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.