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INTRODUCTION
LASL-80-42
October 1980
Vol~m.:tQ~Qgy
at the
Los Alamos Scientific Laboratory
1980
Grant Heiken
On May 18, 1980. when Mount St. Helens erupted, the
American public awoke to the reality of volcanic
phenomena. The turbulent clouds, molten rock, and
acrid smells of a volcanic eruption are indeed awesome.
To the scientist, too, a volcanic eruption is an awesome
spectacle, but a volcano, whether active or inactive, is a
fascinating natural laboratory. The location, age, and.
distinctive features of volcanic f1elds provide clues to the
activity going on beneath the Earth's crust. Erupted
lavas, volcanic ejecta, and gases provide information on
the composition and processes of our planet's interior.
Within the United States during the last 150 years,
volcanoes have erupted in Alaska, Hawaii, California,
~11~ most recendy in Washington.
Volcanic. hazards are multiple. Populated areas. near
volcanoes may be endangered by explosive a~tivity and.
lava flows. The fallout of volcanic ash may ruin water
supplies, crops, viliages, and cities. At greater distances,
gases may severely corrode machinery and vehicles and
can endanger health. Volcanic gas and ash entering the
atmosphere may diffuse across large areas and may
lower atmospheric temperatures. Short-term climatic
changes caused by volcanic eruptions have shortened
growing seasons and produced famine in the Northern
Hemisphere.
On the positive side, young volcanoes overlie great
reservoirs of heat energy that can be used for heating and
generating electricity. Ash falls, in moderate amounts,
enrich the soils around volcanoes. In many tropical
countries, they are necessary for renewal of the soil and
continued agricultural u::e of the land. We must understand volcanoes, their causes, and their activity before
we can develop them as, sources of heat .or avoid their
hazards.
VOLCANIC HAZARD ANALYSIS
University of California
'L\S\.
LOS ALAMOS SCIENTIFIC LABORATORY
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Permission to reproduce this article is granted.
Located on the edge of a geologically young volcanic
field, the Los Alamos Scientific Laboratory (LASL) is
involved in many aspects of volcanology, particularly as
applied to energy, mineral resources, and volcanic hazards. There are several other young volcanic centers in
the Southwest where future volcanic activity is possible.
At present, volcanic activity in the Southwest is less
violent than in the Pacific Northwest. However, even this
relatively "quiet" volcanic activity is a significant factor
in determining the suitability of a nuclear waste disposal
not stop underground, but moved to the surface where it
exploded violently. Currently, LASL scientists are studying Mount St. Helens and plan to increase their involvement there.
CLIMATIC EFFECTS OF VOLCANIC
TIONS
Dissected cinder cone and lava flow at Crater Flat,
Nevada. This volcano erupted 1.1 mil'lion years
ago;" other volcanoes in the region are being studied
to determine the potential hazard to proposed
nuclear waste repositories at the DeJhlrtment of
Energy's Nevada Test Site.
site proposed for the Department of Energy's Nevada
Test Site. The site is nearly ideal because it is dry and
remote. LASL scientists David Vaniman and coworkers
are assessing the possibility of volcanic act1ivity near the
site and the chemical and physical history of recent
volcanism in the area.
Previous work on other volcanoes by LASL scientists
has provided basic information on phreatic (steam)
volcanic eruptions. Through the use of eruption ph()tOgraphs, analyses of the volcanic ash, andi geophysical
measurements, phreatic eruptions were studied at Mount
Baker, Washington (1975) and La Soufriere de
Guadeloupe, French West Indies (1976). At Guadeloupe, LASL scientists were part of an international
team studying the volcano's behavior to determine
if the activity was a forerunner of more energetic, highly
dangerous eruptions. In both areas, the explosive release
of steam was generated by ground water coming into
' contact with hot rock beneath the volcanoes. The
"volcanic ash" from these two eruptions consisted only..
of rock particles torn from the vent by esc:aping steam.
We discovered that the volcanic ash did not contain any
fresh glass particles, which normally indicate the presence of molten rock within the erupted material. The lack
of erupted molten material influenced the dc:cision to end
the evacuation of 80 000 Guadeloupe :residents. At
Mount St. Helens, the early phases of activity were
phreatic; however, unlike the eruptions at La Soufriere
de Guadeloupe and Mount Baker, the molten rock did
ERUP-
Although the relationship between large volcanic
eruptions and short-term climatic changes has been
documented. we lack sufficient data to understand the
changes. The cooperative research now being done by
volcanologists, atmospheric chemists, and meteorologists
at LASL and their counterparts in other government
agencies will increase our understanding of the growth,
dispersion, and composition of volcanic plumes in the
Earth's stratosphere. Key elements of the research
include observing volcanic plumes with satellites and
Iidar (light detection and ranging) and sampling their
contents by high-altitude aircraft. The aircraft sampling
missions flown for LASL after major eruptions of
Soufriere of St. Vincent, British West Indies, in 1979
and Mount St. Helens in 1980 and the follow-up work at
LASL and other laboratories will provide us with
Scanning electron micrograph of volcanic ash from
Mount St. Helens shows a filter sample collected 2
days after the eruption from a stratospheric plume
over western Kansas at an elevation of 15.2 km
(50 000 ft). The particles consist of volcanic glass,
1 flm to 11Jlm in diameter (400 to 40 millionths of
an inch).
,
u3
Scale, km
masses of molt~g, or Pllr.tly .rnolten rock that are located a
few kilometers to several tens of kilometers deep. These
heat reservoirs provide the energy for the highest grade
geothermal resources available to us in the United States.
Some of the larger hot rock masses may have volumes of:
hundreds to thousands of cubic kilometers and can take
up to 2 millicm ~~s to cool to the ambient temperature
of the Earth's crust if they are not reheated by the
intrusion of new magma. Each m~;~.ss holds an enormous
amount of thermal energy. A small amount of this
energy is transferred to the surface during the interaction
with ground water to produce geysers, hot springs, and
natural steam fields, but most of the heat remains locked
into the rock, cooled very slowly by conduction into the
surrounding area.
In its Hot _Dry Rock Geothermal Project, LASL is
experimenting with manmade geothermal systems designed to extract this heat for direc~~ _or for the
generation of electricity. At an experimental site near
Computer plot showing the shock in air and the
ash from an eruption of steam-saturated molten
intrusion. The velocity of the expanding gas and
volcanic ash cloud as it leaves the vent is 125 m/s
(279 mph).
information on particle concentrations; compositions,
and distributions in the plumes and will make these
volcanic eruption plumes the best studied in history.
The study of volcanic plumes, which are natural
examples of the massive injection of particulates into the
atmosphere, helps scientists determine if increased production of energy from fossil fuels will harm the Earth's
~£timate through particulate pollution. In addition to
climatic-effects applications, the data on eruption plumes
will be applied to studies of hazards to aircraft that might
pass through them.
In a cooperative study with the Smithsonian Institution, the LASL computer facility is being used to
construct numerical models of large volcanic blasts like
the 1883 eruption of Krakatoa in Indonesia and the
recent eruption of Mount St. Helens. The models are
used to determine the nature and extent of atmospheric
shock waves and the nature of outflow and fallout of
ejecta.
-YOUNG VOLCANIC FIELDS AS HEAT SOURCES
Volcanology can also contribute to the se:arch for
alternative energy sources. Young volcanoes overlie
The Jemez Mountains in northern New Mexico are
composed of volcanic rocks, which have erupted
over the last 10 million years; some are as young
' feature in this
as 50,000 years. The large circular
spacecraft image is the 22 km (14 mi) diameter
Valles Caldera, a volcanic collapse feature. Associated with this caldera is a geothermal anomaly; within the anomaly, the natural hot water is
being developed by a local utility company and heat
is being extracted from impermeable portions by
the LASL Hot Dry Rock Geothermal Project.
I
Los Alamos, t\YQ..dc;Cp wells in natural hot dry rock are
connected with a manmade hydraulic fracture. Water is
circulated through the loop; where the temperatures are
as high as 200°~~ (3,?2°F), to produce hot water and
steam. Because the highest grade geothermal resources
are associated with volcanic fields, work at LASL is
directed at understanding the "plumbing" below these
fields, its role as a heat squrce, and its relation to surface
features such as volcanic vents and large volcanic
collapse features. Through this work, we hope to understand the 'nature and magnitude of the hot dry rock
geothermal resource at each of the many young volcanic
fields within the United States.
VOLCANIC ASH DEPOSITS AND NUCLEAR
WASTE ISOLATION
LASL research on the present physical and .mineralogical properties of these volcanic deposits, formed
during explosive eruptions nearly 15 million years ago,
may provide acceptable locations for tht: storage of
nuclear wastes. Of interest are old, thick volcanic. ash
deposits located in isolated parts of the western United
States. LASL scientists are studying deposits in Nevada
that consisted of glassy, silica-rich volcanic ash particles
that were transformed into zeolites and other minerals
during interaction with circulating ground water. Zeolite
minerals have internal crystal structures <:onsisting of
open frameworks that allow them to be used commercially to filter radionuclides from contaminated effluents.
The zeolite-rich, thick volcanic ash deposits would thus
act as a natur!l barrier against radionuclide migration
from a nuclear-waste repository.
BASIC RESEARCH
Basic research by geologists at LASL on the origins of
volcanism an~ the association of volcanoes with major
structural features of the North American continent. has
long-term applications. The J~~~.!olcanic lineament of
Arizona and New Mexico and the Rio Grande rift of
Chihuahua, Texas, New Mexico, and Colorado are the
subjects of several LASL studies. The relations of the
volcanoes and volcanic fields to these structural features
and the changes in composition and distribution of
volcanic rocks along them provide clues to their origin
and to the distribution of geothermal anomalies and ore
bodies associated with these major structural lineaments.
THE FUTURE
Voh.:anQlqgy is an actively growing science and there is
much to be learned. We must accumulate data on
phenomena preceding eruJ)tions to develop the capability
for prediction, and to understand and cope with the
potential hazards to man. We also must increase our
understanding of the beneficial aspects. For example, the
eruption of Mount St. Helens caused tragedy .for many
people, but it also pointed out that within t~~.Cascade
Range is a large geothermal resource to be developed.
Volcanic danger and volcanic benefits both require
long-term research commitments if our studies are to be
productive.
Mini-Review
readerscare encouraged
to correspond directly
with the author.
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