USGS/Cascades Volcano Observatory, Vancouver, Washington
DESCRIPTION:
Silver Lake, Mount St. Helens, Washington
- Silver Lake
- Silver Lake Visitor Center
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Silver Lake with Mount St. Helens in the background
-- USGS Photo by Lyn Topinka, September 15, 1980
From:
Pringle, 1993,
Roadside Geology of Mount St. Helens National Volcanic Monument and Vicinity:
Washington Department of Natural Resources
Division of Geology and Earth Resources Information Circular 88, p.42.
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Silver Lake is shallow (maximum depth about 16 feet or 5 meters)
and was formed and is
partially underlain by lahar deposits. About 2,500 years ago during the Pine
Creek eruptive period, a series of very large lahars traveled down the Toutle
River from Mount St. Helens. The lahars flowed into Outlet Creek (east of the
lake) and dammed its valley to produce Silver Lake. These lahars were generated
by the catastrophic draining of a lake (presumably an older Spirit Lake) or
lakes that had been dammed by debris avalanches from Mount St. Helens. The
level of Silver Lake is now controlled by a dam.
From:
Mullineaux and Crandell, 1981,
The Eruptive History of Mount St. Helens:
IN:
Lipman and Mullineaux (eds.), 1981,
The 1980 Eruptions of Mount St. Helens, Washington:
USGS Professional Paper 1250, 844p.
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... During the
Pine Creek eruptive period (3,000 - 2,500 years ago),
large pumiceous and lithic pyroclastic flows moved away from the volcano
(Mount St. Helens) in nearly all directions.
The lithic pyroclastic flows, some of
which extended as far as 18 kilometers from the present center of the volcano,
are believed to have been derived from dacite domes. Eruptions of dacitic
airfall tephra were of small volume, but at least four formed recognizable
layers as far away as Mount Rainier (Mullineaux, 1974, p.36).
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During this time, lahars and fluvial deposits aggraded the valley floors of both
North and South Fork Toutle River, and created the basin of Silver Lake,
50 kilometers west-northwest of the volcano by blocking a tributary valley
(Mullineaux and Crandell, 1962). ...
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Silver Lake Visitor Center
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From:
Pringle, 1993,
Roadside Geology of Mount St. Helens National Volcanic Monument and Vicinity:
Washington Department of Natural Resources
Division of Geology and Earth Resources Information Circular 88, p.42.
-
Mount St. Helens National Volcanic Monument Visitor Center
--
Operated by the U.S. Forest Service, the visitor center is an excellent
orientation point for the western approach to Mount St. Helens. A variety of
educational displays can be viewed, and maps, audiovisual materials, and books
are available at the center. Movies and slide shows are generally scheduled on
the half hour, punctuated occasionally by special presentations and lectures.
Weather permitting, Mount St. Helens can be seen 30 miles
(48 kilometers) to the east across
Silver Lake. The stone used to construct the center and the low walls around
the building is a welded tuff quarried in the Oregon Cascades.
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URL for CVO HomePage is:
<http://vulcan.wr.usgs.gov/home.html>
URL for this page is:
<http://vulcan.wr.usgs.gov/Volcanoes/MSH/Hydrology/Lakes/SilverLake/description_silver_lake.html>
If you have questions or comments please contact:
<GS-CVO-WEB@usgs.gov>
04/21/08, Lyn Topinka
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