Mount St. Helens: A Catalyst for Change
Detailed Description
The May 18, 1980 eruption of Mount St. Helens triggered a growth in volcano science and volcano monitoring. Five USGS volcano observatories have been established since the eruption. With new technologies and improved awareness of volcanic hazards USGS scientists are helping save lives and property across the planet.
Details
Date Taken:
Length: 06:46:00
Location Taken: Skamania County, WA, US
Transcript
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Narrator:
The May 18,
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1980 eruption of Mount St. Helens was
a seminal moment for volcanology
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On that fateful morning, an
earthquake and giant landslide
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uncorked a lateral blast that
flattened 230 square miles...
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in a matter of minutes.
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For nine hours after that,
a vigorous eruption column
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billowed into the atmosphere
coating everything downwind
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with ash. Local rivers were
inundated by mudflows and debris
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flows that took out bridges
and homes for miles downstream.
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For two months prior to May
18, 1980 scientists with the
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U.S. Geological Survey and
the University of Washington’s
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Pacific Northwest Seismographic
Network were closely
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monitoring Mount St. Helens.
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C. Dan Miller:
But it was truly
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only the beginning of an eruptive episode that
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lasted for over 6 years. So
the first explosion occurred
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on May 18 and then there were
several sizeable explosions in
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the summer of 1980 and they
sort of trailed off until
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October of 1980 and then for
the next five years or five and
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a half years there were a series
of dome building eruptions
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in which molten material came
out, very viscous pasty lava
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come out on the floor of the
crater and piled up to form a
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dome or a mound in the middle
of the crater floor a feature
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that’s now about 900 feet high
sitting on the floor of the crater.
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So, this episode at Mount St.
Helens which began on May 18
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actually culminated in October
of 1986 when the last magma
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came out of the ground.
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Narrator
The volcano
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reawakened again in 2004 displaying another period
of dome building and smaller explosive eruptions.
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This resumed unrest was an
opportunity for the scientists
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to deploy new and improved monitoring equipment.
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Dan Dzurisin
Today we deployed
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with a helicopter a multi-sensor instrument
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package that was developed literally
in the past week or at least
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fabricated in the past week at
the Cascades Volcano Observatory.
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This was in response to what
we’ve been learning at the volcano
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over the past two and a half to
three weeks. The first thing we
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did was deploy ground deformation instruments
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out on the outer flanks of
the volcano and learned that
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they weren’t moving. Then last
week we deployed three GPS
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instruments on the old part
of the lava dome itself.
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And discovered that it’s moving
very little if at all at the
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same time that the feature on
the south crater floor is moving
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by tens of meters and so we
wanted to get instruments directly
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on the part of the dome
that’s moving so dramatically.
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And so we very quickly put together
a GPS sensor, a seismometer,
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a tilt meter and a microphone,
the microphone will record the
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sound of explosions should they
occur and that’s important if they
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occur in the middle of night or in
bad weather we’ll have some indication
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that that’s what's happened and
integrate that into our data stream.
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We’d like to know for example
is the deformation continuing?
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Is the rate increasing or
decreasing? How does the rate
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correlate with seismic
activity? When we’re having more
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earthquakes is the ground
deforming more rapidly or less
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rapidly because it’s easier
for magma to move up the pipe?
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And therefore producing fewer
earthquakes. We don’t know
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such fundamental things. And
understanding those kinds of
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relationships is key to trying
to interpret the processes that
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are going on understanding where
the volcano might be headed
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and therefore mitigating any hazards
associated with future activity.
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Narrator:
Volcano
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science and volcano monitoring have developed
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impressively since May 18,
1980. Technology such as GPS,
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infrared imaging, acoustic
flow sensors and Dopler Radar
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are just a few of the new tools
available to the scientists.
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They are studying hazards
from lava flows to explosive
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eruptions, mud flows, debris
flows, debris avalanches and
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airborne volcanic ash. The
realization that volcanic ash can
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stall a jet engine adds
urgency to monitoring explosive
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eruptions and any ash clouds
that may threaten aircraft.
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In the US and its territories
there are 169 volcanoes capable
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of erupting. With responsibility
for monitoring these
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volcanoes the USGS now operates
volcano observatories focused
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on Hawaii, Alaska, The Cascades, Yellowstone and
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Long Valley in California.
One important aspect of this
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operation is the Volcano Disaster
Assistance Program (VDAP)...
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a team of scientists with a
cache of monitoring gear that
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responds to volcanic unrest across the planet.
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Among the VDAP success stories
was the forecasting of the
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1991 Mt. Pinatubo, Philippines
eruption in time to save
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thousands of lives and to
evacuate planes and people from
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US run Clark Air Base.
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Awe inspiring, spectacular
and scary all characterize the
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eruption of Mount St. Helens on May 18, 1980.
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The human response to this
catastrophic event has laid the
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groundwork for saving lives
and better addressing future
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volcanic eruptions wherever they might occur.