Mount St. Helens: A Catalyst for Change

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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.