Dataset Identification:
Resource Abstract:
- description: The word volcano is used to refer to the opening from which molten rock and gas issue from Earth's interior
onto the surface, and also to the cone, hill, or mountain built up around the opening by the eruptive products. This slide
set depicts ash clouds, fire fountains, lava flows, spatter cones, glowing avalanches, and steam eruptions from 18 volcanoes
in 13 countries. Volcano types include strato, cinder cone, basaltic shield, complex, and island-forming. Perhaps no force
of nature arouses more awe and wonder than that of a volcanic eruption. Volcanoes can be ruthless destroyers. Primitive people
offered sacrifices to stem the tide of such eruptions and many of their legends were centered around volcanic activity. Volcanoes
are also benefactors. Volcanic processes have liberated gases of the atmosphere and water in our lakes and oceans from the
rocks deep beneath Earth's surface. The fertility of the soil is greatly enhanced by volcanic eruptive products. Land
masses such as islands and large sections of continents may owe their existence entirely to volcanic activity. The "volcano"
is used to refer to the opening from which molten rock and gas issue from Earth's interior onto the surface, and also
to the cone, hill, or mountain built up around the opening by the eruptive products. The molten rock material generated within
Earth that feeds volcanoes is called magma and the storage reservoir near the surface is called the magmachamber. Eruptive
products include lava (fluid rock material) and pyroclastics or tephra (fragmentary solid or liquid rock material). Tephra
includes volcanic ash, lapilli (fragments between 2 and 64 mm), blocks, and bombs. Low viscosity lava can spread great distances
from the vent. Higher viscosity produces thicker lava flows that cover less area. Lava may formlava lakes of fluid rock in
summit craters or in pit craters on the flanks of shield volcanoes. When the lava issues vertically from a central vent or
a fissure in a rhythmic, jet-like eruption, it produces a lava fountain. Pyroclastic (fire-broken) rocks and rock fragments
are products of explosive eruptions. These may be ejected more or less vertically, thenfall back to Earth in the form of ash
fall deposits. Pyroclastic flows result when the eruptive fragments follow the contours of the volcano and surrounding terrain.
They are of three main types: glowing ash clouds, ash flows, and mudflows. A glowing ash cloud (nuee ardente) consists of
an avalanche of incandescent volcanic fragments suspended on a cushion of air or expanding volcanic gas. This cloud forms
from the collapse of a vertical ash eruption, from a directed blast, or is the result of the disintegration of a lava dome.
Temperatures in the glowing cloud can reach 1,000 deg C and velocities of 150 km per hour. Ash flows resemble glowing ash
clouds; however, their temperatures are much lower. Mudflows (lahars) consist of solid volcanic rock fragments held in water
suspension. Some may be hot, but most occur as cold flows. They may reach speeds of 92 km per hour and extend to distances
of several tens of kilometers. Large snow-covered volcanoes that erupt explosively are the principal sources of mud flows.
Explosions can give rise to air shock waves and base surges. Air shock waves are generated as a result of the explosive introduction
of volcanic ejecta into the atmosphere. A base surge may carry air, water, and solid debris outward from the volcano at the
base of the vertical explosion column. Volcanic structures can take many forms. A few of the smaller structures built directly
around vents include cinder, spatter, and lava cones. Thick lavas may pile up over their vents to form lava domes. Larger
structures produced by low viscosity lava flows include lava plains and gently sloping cones known as a shield volcanoes.
A stratovolcano (also known as a composite volcano) is built of successive layers of ash and lava. A volcano may consist of
two or more cones side by side and is referred to as compound or complex. Sometimes a violent eruption will partially empty
the underground reservoir of magma. The roof of the magma chamber may thenpartially or totally collapse. The resulting caldera
may be filled by water. The volcanic structure tells us much about the nature of the eruptions.; abstract: The word volcano
is used to refer to the opening from which molten rock and gas issue from Earth's interior onto the surface, and also
to the cone, hill, or mountain built up around the opening by the eruptive products. This slide set depicts ash clouds, fire
fountains, lava flows, spatter cones, glowing avalanches, and steam eruptions from 18 volcanoes in 13 countries. Volcano types
include strato, cinder cone, basaltic shield, complex, and island-forming. Perhaps no force of nature arouses more awe and
wonder than that of a volcanic eruption. Volcanoes can be ruthless destroyers. Primitive people offered sacrifices to stem
the tide of such eruptions and many of their legends were centered around volcanic activity. Volcanoes are also benefactors.
Volcanic processes have liberated gases of the atmosphere and water in our lakes and oceans from the rocks deep beneath Earth's
surface. The fertility of the soil is greatly enhanced by volcanic eruptive products. Land masses such as islands and large
sections of continents may owe their existence entirely to volcanic activity. The "volcano" is used to refer to
the opening from which molten rock and gas issue from Earth's interior onto the surface, and also to the cone, hill,
or mountain built up around the opening by the eruptive products. The molten rock material generated within Earth that feeds
volcanoes is called magma and the storage reservoir near the surface is called the magmachamber. Eruptive products include
lava (fluid rock material) and pyroclastics or tephra (fragmentary solid or liquid rock material). Tephra includes volcanic
ash, lapilli (fragments between 2 and 64 mm), blocks, and bombs. Low viscosity lava can spread great distances from the vent.
Higher viscosity produces thicker lava flows that cover less area. Lava may formlava lakes of fluid rock in summit craters
or in pit craters on the flanks of shield volcanoes. When the lava issues vertically from a central vent or a fissure in a
rhythmic, jet-like eruption, it produces a lava fountain. Pyroclastic (fire-broken) rocks and rock fragments are products
of explosive eruptions. These may be ejected more or less vertically, thenfall back to Earth in the form of ash fall deposits.
Pyroclastic flows result when the eruptive fragments follow the contours of the volcano and surrounding terrain. They are
of three main types: glowing ash clouds, ash flows, and mudflows. A glowing ash cloud (nuee ardente) consists of an avalanche
of incandescent volcanic fragments suspended on a cushion of air or expanding volcanic gas. This cloud forms from the collapse
of a vertical ash eruption, from a directed blast, or is the result of the disintegration of a lava dome. Temperatures in
the glowing cloud can reach 1,000 deg C and velocities of 150 km per hour. Ash flows resemble glowing ash clouds; however,
their temperatures are much lower. Mudflows (lahars) consist of solid volcanic rock fragments held in water suspension. Some
may be hot, but most occur as cold flows. They may reach speeds of 92 km per hour and extend to distances of several tens
of kilometers. Large snow-covered volcanoes that erupt explosively are the principal sources of mud flows. Explosions can
give rise to air shock waves and base surges. Air shock waves are generated as a result of the explosive introduction of volcanic
ejecta into the atmosphere. A base surge may carry air, water, and solid debris outward from the volcano at the base of the
vertical explosion column. Volcanic structures can take many forms. A few of the smaller structures built directly around
vents include cinder, spatter, and lava cones. Thick lavas may pile up over their vents to form lava domes. Larger structures
produced by low viscosity lava flows include lava plains and gently sloping cones known as a shield volcanoes. A stratovolcano
(also known as a composite volcano) is built of successive layers of ash and lava. A volcano may consist of two or more cones
side by side and is referred to as compound or complex. Sometimes a violent eruption will partially empty the underground
reservoir of magma. The roof of the magma chamber may thenpartially or totally collapse. The resulting caldera may be filled
by water. The volcanic structure tells us much about the nature of the eruptions.
Citation
- Title Volcanoes in Eruption - Set 2.
-
- creation Date
2015-11-10T08:22:14.355635
Resource language:
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Metadata data stamp:
2018-08-06T22:38:37Z
Resource Maintenance Information
- maintenance or update frequency:
- notes: This metadata record was generated by an xslt transformation from a dc metadata record; Transform by Stephen M. Richard, based
on a transform by Damian Ulbricht. Run on 2018-08-06T22:38:37Z
Metadata contact
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pointOfContact
- organisation Name
CINERGI Metadata catalog
-
- Contact information
-
-
- Address
-
- electronic Mail Address cinergi@sdsc.edu
Metadata language
eng
Metadata character set encoding:
utf8
Metadata standard for this record:
ISO 19139 Geographic Information - Metadata - Implementation Specification
standard version:
2007
Metadata record identifier:
urn:dciso:metadataabout:45bbdab5-ad21-44cb-a3ae-d8f0d1025941
Metadata record format is ISO19139 XML (MD_Metadata)