USGS/Cascades Volcano Observatory, Vancouver, Washington
DESCRIPTION:
Glacier Peak Volcano, Washington
- Glacier Peak
- Historical Information
- Eruptive History
-
GP07_glacier_peak_from_east_08-02-07.jpg
Glacier Peak as viewed from the east.
USGS photo taken on August 2, 2007, by Jim Vallance.
[medium size] ...
[large size] ...
[TIF Format, 18 M]
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:
Mastin and Waitt, 2000, Glacier Peak --
History and Hazards of a Cascade Volcano:
USGS Fact Sheet 058-00
-
Glacier Peak is the most remote of the five active volcanoes in
Washington State. It is not prominently visible from any major
population center, and so its attractions, as well as its hazards, tend to
be over-looked. Yet since the end of the last ice age, Glacier Peak has
produced some of the largest and most explosive eruptions in the
state. During this time period, Glacier Peak has erupted multiple times
during at least six separate episodes, most recently about 300 years
ago. ...
-
The stunning snow-capped volcanoes of Washington State have long been recognized by Native Americans
in their language and legends, and they immediately caught the eyes of
U.S. and European explorers in the
late 18th and early 19th centuries. By the 1790s,
Mounts Baker,
Rainier, and
St. Helens
were noted and
named in the first written descriptions of the Columbia River and Puget Sound regions. In 1805 Lewis and
Clark noted
Mount Adams.
By the mid-19th century each of these four volcanoes had their place on a
published map.
-
Glacier Peak wasn't known by settlers to be a volcano until the 1850s, when Native Americans mentioned
to naturalist George Gibbs that "another smaller peak to the north of Mount Rainier once smoked." Not until
1898 did Glacier Peak appear on a published map under its current name.
-
Glacier Peak lies only 70 miles northeast of Seattle -- closer to that city than any volcano except
Mount Rainier.
But unlike Mount Rainier, it rises only a few thousand feet above neighboring peaks, and from
coastal communities it appears merely as a high point along a snowy saw-toothed skyline. Yet Glacier Peak
has been one of the most active and explosive of Washington's volcanoes.
-
Since the continental ice sheets receded from the region, Glacier Peak has erupted repeatedly during at
least six episodes. Two of these eruptions were among the largest in Washington during the past 15,000
years. These pages describe some of the effects of past eruptions and possible consequences of future
activity.
From:
Wood and Kienle, (eds.), 1990,
Volcanoes of North America - United States and Canada:
Cambridge University Press, p.156-158,
Contribution by Jim Beget
-
Glacier Peak (3,213 meters) is a small Cascade Range
stratovolcano.
Although its summit reaches greater then 3,000 meters above the surrounding valleys, the main
cone of Glacier Peak is perched on a high ridge, and the volcanic pile is no more than
500-1,000 meters thick.
More than a dozen glaciers occur on the flanks of the volcano, and unconsolidated pyroclastic
deposits over 12,000 years old have been largely removed by glaciation. Lava flows locally cap
ridges to the northeast of the volcano, indicating a topographic reversal, and glacial and
fluvial downcutting of more than 2,000 meters has occurred since the earliest cone-building
eruptions.
While small basaltic flows and cones are found at
several points around the flanks of Glacier Peak, the main edifice is largely dacite and
andesite. Lava flows extend no more than a few kilometers from the summit.
From:
Mastin and Waitt, 2000, Glacier Peak --
History and Hazards of a Cascade Volcano:
USGS Fact Sheet 058-00
-
The stunning snow-capped volcanoes of Washington State have long been recognized by Native Americans
in their language and legends, and they immediately caught the eyes of
U.S. and European explorers in the
late 18th and early 19th centuries. By the 1790s,
Mounts Baker,
Rainier, and
St. Helens
were noted and
named in the first written descriptions of the Columbia River and Puget Sound regions. In 1805 Lewis and
Clark noted
Mount Adams.
By the mid-19th century each of these four volcanoes had their place on a
published map.
-
Glacier Peak wasn't known by settlers to be a volcano until the 1850s, when Native Americans mentioned
to naturalist George Gibbs that "another smaller peak to the north of Mount Rainier once smoked." Not until
1898 did Glacier Peak appear on a published map under its current name.
From:
Wood and Kienle, (eds.), 1990,
Volcanoes of North America - United States and Canada:
Cambridge University Press, p.156-158,
Contribution by Jim Beget
-
Indian legends and a thin tephra fall preserved east of the volcano may record a recent
eruption in the 18th century, although no eruptive activity has occurred during at least the
last 150 years.
From:
U.S. Forest Service, Wenatchee National Forest Website, 2002
-
For thousands of years Native Americans traveled through this area
to the meadows and peaks of the North Cascades in search of
plants and game. The first white man to record seeing
Glacier Peak was Daniel Linsley,
surveying in 1870 for a possible railroad route
for the Northern Pacific Railroad.
Mining claims were filed in the Glacier Peak
area during the North Cascades "gold rush" of the 1880s
and 1890s. Except for the Holden Mine, just east of the Wilderness,
all that remains of early day mining and trapping activities are
abandoned mine shafts, rusting equipment, and a few rotting cabins.
From:
Wood and Kienle, (eds.), 1990,
Volcanoes of North America - United States and Canada:
Cambridge University Press, p.156-158,
Contribution by Jim Beget
-
Glacier Peak is probably best known as the source of voluminous tephra eruptions dated to
11,250 years B.P. Two tephra layers produced at this time have been identified as far as
800-1,000 kilometers to the east, and are widely used by geologists, anthropologists, and
paleoecologists to date late Pleistocene sediments. Also at this time, an extensive valley
fill of pumiceous lahars and alluvium was deposited downriver to the west, blocking valleys and
affecting drainages as far as 80 kilometers from the volcano.
-
After these major eruptions, Glacier Peak apparently was dormant for 6,000 years. The volcano
rewoke 5,500-5,100 years B.P. and intermittent eruptions of pyroclastic flows and tephra have
occurred since that time. perhaps the most dramatic geologic features at Glacier Peak are
enormous and relatively undissected late Pleistocene and Holocene pyroclastic fans which almost
completely fill valleys on the eastern and western flanks of the volcano.
-
Indian legends and a thin tephra fall preserved east of the volcano may record a recent
eruption in the 18th century, although no eruptive activity has occurred during at least the
last 150 years. Three hot springs surround the volcano, and warm ground and snow-free areas
occur near fresh-appearing dacite domes which form subsidiary summits both north and south of
the ice-covered main summit.
From:
Mastin and Waitt, 2000, Glacier Peak -- History and Hazards of a Cascade Volcano:
USGS Fact Sheet 058-00
-
Glacier Peak and
Mount St. Helens
are the only volcanoes in Washington State that have generated large,
explosive eruptions in the past 15,000 years. Their violent behavior results from the type of molten rock
(magma) they produce. Dacite, the typical magma type of Mount St. Helens and Glacier Peak, is too viscous
to flow easily out of the eruptive vent; it must be pressed out under high pressure. As it approaches the
surface, expanding gas bubbles within the magma burst and break it into countless fragments. These
fragments are collectively known as tephra; the smallest are called ash.
-
About 13,100 years ago, Glacier Peak generated a sequence of nine tephra eruptions within a period of less
than a few hundred years. The largest ejected more than five times as much tephra as the
May 18, 1980, eruption of Mount St. Helens
and was one of the largest in the Cascade Range since the end of the last ice
age.
-
Some of the tephra from these eruptions fell back onto the volcano and avalanched down its flanks. Much
of the rest rose high into the atmosphere and drifted hundreds to thousands of miles downwind. Deposits
from these eruptions are more than a foot thick near Chelan, Washington, and an inch thick in western
Montana.
-
Since these events, Glacier Peak has produced several tephra eruptions, all of much smaller volume.
-
During most of Glacier Peak's eruptive episodes, lava domes have extruded onto the volcano's summit or
steep flanks. Parts of these domes collapsed repeatedly to produce pyroclastic flows and ash clouds. The
remnants of prehistoric lava domes make up Glacier Peak's main summit as well as its "false summit"
known as Disappointment Peak. Pyroclastic-flow deposits cover the valley floors east and west of the
volcano. Ridges east of the summit are mantled by deposits from ash clouds.
-
Past eruptions have severely affected river valleys that head on Glacier Peak. Pyroclastic flows mixed with
melted snow and glacial ice to form rapidly flowing slurries of rock and mud known as lahars.
-
About 13,100 years ago, dozens of eruption-generated lahars churned down the White Chuck, Suiattle, and
Sauk Rivers, inundating valley floors. Lahars then flowed down both the North Fork Stillaguamish (then an
outlet of the upper Sauk River) and Skagit Rivers to the sea. In the Stillaguamish River valley at Arlington,
more than 60 miles downstream from Glacier Peak, lahars deposited more than seven feet of sediment.
Shortly after the eruptions ended, the upper Sauk's course via the Stillaguamish was abandoned and the
Sauk River began to drain only into the Skagit River, as it does today.
-
About 5,900 years ago and 1,800 years ago, dome-building eruptions generated lahars that extended once
again to the sea, this time only along the Skagit River. In small eruptions since 1,800 years ago, lahars
have extended the entire length of the White Chuck River and part way down the Suiattle.
-
Lahars can also be generated by landslides (also called flank collapses) on volcanoes, as has happened
repeatedly at Glacier Peak's neighbor to the north,
Mount Baker.
At Mount Baker, lahars from numerous
landslides, some without accompanying eruptive activity, have affected valley floors near the volcano. A
few much larger landslides during eruptive periods generated lahars that flowed hundreds of feet deep
through upper valleys and reached the sea. At Glacier Peak landslide-generated lahars have occurred less
frequently than at Mount Baker.
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 a
Pleistocene 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:
- 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),
- seven tephra falls of small (0.01-0.1 cubic kilometers)
volume (Porter, 1978), and
- 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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07/21/02, Lyn Topinka