Glacier Peak
Glacier Peak is a glaciated stratovolcano in Washington’s Cascade Range. Its explosive eruptions have produced extensive ash and debris deposits.
Stratovolcano: A steep, layered volcano built chiefly from lava flows, ash, and other volcanic deposits. Glacier Peak’s steep cone and alternating eruptive deposits fit this broad volcano type.
Holocene: The current geological epoch, beginning about 11,700 years ago after the last glacial period. Several of Glacier Peak’s major explosive eruptions occurred during this epoch.
United States Geological Survey: A federal scientific agency that studies geology, natural hazards, water, and ecosystems in the United States. The agency monitors Cascade volcanoes and assesses hazards from Glacier Peak.
Cascade Range: A mountain range extending from British Columbia through Washington and Oregon into northern California. Glacier Peak rises within the volcanic and glaciated terrain of the North Cascades.
Glacier Peak eruption of 1980: A minor eruptive episode at Glacier Peak in 1980, involving steam and ash emissions. It is the volcano’s most recent reported eruptive activity.
Tephra: Fragmented material ejected into the air during a volcanic eruption. Explosive eruptions of Glacier Peak spread tephra across large parts of Washington.
Set A tephra: A widespread tephra deposit produced by a major explosive eruption of Glacier Peak. This deposit records one of the volcano’s largest Holocene eruptions.
Volcano monitoring: The systematic observation of volcanic activity to detect changes that may signal an eruption. Seismic, gas, and ground-deformation measurements help track changes at Glacier Peak.
Mount Baker: An active stratovolcano in the North Cascades of Washington. It is a nearby Cascade volcano with its own ice-related hazards.
Glacier Peak eruptive history: The sequence of volcanic eruptions and deposits that documents Glacier Peak’s development. Its record includes explosive eruptions that dispersed ash far beyond the mountain.