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DESCRIPTION:
Glacier Peak Volcano, Washington
Compiled From: 1 Smithsonian Institution - Global Volcanism Program Website, 1998, 2 Wright and Pierson, 1992, Living With Volcanoes, The U.S.Geological Survey's Volcano Hazards Program: USGS Circular 1073, and 3 Foxworthy and Hill, 1982, Volcanic Eruptions of 1980 at Mount St. Helens, The First 100 Days: USGS Professional Paper 1249
Location: Washington
Latitude: 48.112 N
Longitude: 121.113 W
Height: 3,213 Meters (10,541 Feet)
Type:Stratovolcano
Number of eruptions in past 200 years: More than 1 (?) (Before 1800) 2
Latest Eruptions: About 200-300 years ago; 1,000-1,800 years ago; 1,800-2,800 years ago 3.
Present thermal activity: Two hot springs on the volcano's lower flanks.
Remarks: Eruptions have characteristically produced large volumes of volcanic ash and airborne pumice that could endanger closest centers of population 3.
From: Mastin and Waitt, 1995, Is Glacier Peak a Dangerous Volcano?: USGS Open-File Report 95-413
Glacier Peak is not prominently visible from any major metropolitan centers, and so its attractions, as well as its hazards, tend to be overlooked. Yet, Glacier Peak has produced larger and more explosive eruptions than any other Washington volcano except Mount St. Helens. In the past 14,000 years, Glacier Peak has erupted at least a dozen times, most recently around the eighteenth century.
From: Hoblitt, Miller, and Scott, 1987, Volcanic Hazards with Regard to Siting Nuclear-Power Plants in the Pacific Northwest: USGS Open-File Report 87-297
Glacier Peak, geographically the most remote of the Cascade volcanoes, is aPleistocene and Holocene composite volcano composed chiefly of dacite, with a minor amount of basalt erupted from satellitic vents (Tabor and Crowder, 1969; Beget, 1982, 1983). Large explosive eruptions about 11,000- 12,000 years ago produced:
1. two tephra-fall deposits of large (>1 cubic kilometer, dense-rock equivalent) volume, which are widely distributed east of the volcano (Lemke and others, 1975; Porter, 1978; Sarna-Wojcicki and others, 1983; Mehringer and others, 1984),
2. seven tephra falls of small (0.01-0.1 cubic kilometers) volume (Porter, 1978), and
3. many pyroclastic-flow deposits and lahars that form thick (locally >100 meters) fills in the valleys that head on the volcano (Tabor and Crowder, 1969; Beget, 1982, 1983).
The two large tephra eruptions were separated in time by probably no more than a few centuries (Mehringer and others, 1984). Tephra of each eruption is about 1 meter thick at a distance of 50 kilometers downwind from the volcano, and about 0.5 meters thick at a distance of 70 kilometers (Porter, 1978). These deposits represent two of the largest Cascade tephra eruptions of postglacial time, although they are less voluminous than the tephra fall that accompanied the climactic eruption of Mount Mazama (about 34 cubic kilometers, dense-rock equivalent).
Pyroclastic flows associated with the eruptive period of 11,000-12,000 years ago traveled as far as 15 kilometers from the volcano, and lahars reached areas along the Stillaguamish and Skagit Rivers more than 100 kilometers from the volcano (Beget, 1982, 1983).
Beget (1982, 1983) also describes Holocene eruptions, associated with dome extrusion near the summit, which produced lahars, pyroclastic flows, and minor tephra. The tephra and pyroclastic flows were less extensive than those of the eruptive period of 11,000-12,000 years ago. Several Holocene lahars extended tens of kilometers downvalley, and two reached distances of more than 100 kilometers.
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