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CURRENT VOLCANIC ACTIVITY
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VOLCANO CAM (Volcano WebCams)
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Mount St. Helens VolcanoCam
Mount St. Helens National Volcanic Monument,
USDA Forest Service, U.S. Department of Agriculture (USDA)
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Mt. St. Helens WA Seismograph
Current Webicorders,
The Pacific Northwest Seismograph Network (PNSN),
Earth and Space Sciences (ESS),
The University of Washington (UW) & partners
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The Old Faithful WebCam
The Official Website of Yellowstone National Park,
National Park Service (NPS),
U.S. Department of the Interior
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VOLCANO OBSERVATORIES &
VOLCANOLOGY INSTITUTES
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U.S. Volcano Observatories & Agencies
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U.S. Geological Survey
Volcano Hazards Program
U.S. Geological Survey (USGS),
U.S. Department of the Interior
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Asian Volcano Observatories & Institutes
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VOLCANIC HOTSPOTS
(Volcanic Hot Spots)
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What Can Seismology Say About Hot Spots?
Bruce R. Julian & Gillian R. Foulger,
U.S. Geological Survey (USGS),
U.S. Department of the Interior &
Department of Geological Sciences,
University of Durham (Durham, UK)
(Adobe PDF file)
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www.MantlePlumes.org
Gillian R. Foulger, www.mantleplumes.org,
Department of Geological Sciences,
University of Durham (Durham, UK)
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Yellowstone Hotspot
Robert B. Smith,
College of Mines and Earth Sciences (CMES),
University of Utah (the U)
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Volcanoes are a natural consequence of plate tectonics and
mantle convection. Tectonic plates, sinking into
the mantle at their edges (a process known as subduction, produce
frictional heating as they grind against one another. This heating,
together with the heat of the mantle, melts crustal rock which combines
with mantle rock. Once the rock has melted, lighter, less dense
components separate out and rise toward the surface.
As the lighter melted material slowly rises, it penetrates into the Earth’s crust, eventually
pooling beneath the Earth’s surface to form magma chambers. When
one of these chambers breaches the crustal surface (lithosphere), a
volcano is born. Another mechanism capable of producing a volcano is a
mantle plume. Mantle plumes are massive ascending currents
within the Earth’s mantle. These create hot spots within
the lithosphere where the plumes create huge upwelling magma chambers.
As the tectonic plates move over the relatively stationary plumes (a
process that occurs over millions of years), a string of volcanoes (such
as the Hawaiian Islands) or calderas (such as Yellowstone) are formed.
Follow links to the right to learn more about volcanoes and volcanology.
At the left margin, Related Links address topics of interest
pertaining to volcanoes, including
volcanic
hazards such as lahars — dangerous
flows
of mud and debris resulting from volcanic eruptions — and
pyroclastic flows — even more deadly eruptions of hot gas
and rock. View the
Technology
& Science SiteMap for a complete list of our technology and
science-related topics.
See
Tech, Science & Engineering Jobs and
Earth
& Space Sciences Jobs if you are seeking a career in
volcanology or volcano research.
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