2. Where is it?
Mount St. Helens is
located in Washington
State. Washington State
is in the North West
region of the United
State and is above Oregon
State. It is around 100
miles from Seattle and 50
miles from Portland.
3. About Mount
St. Helens
Mount St. Helens is 4,400 feet
high at its highest point.It is
also around 6 miles wide at the
base! The snow on the slopes of
Mount St. Helens is usually 15
feet deep, but it can get as
deep as 25 feet at some
times.Mount St. Helens is a
composite volcano, and it is
less than 3,000 years old,
making it younger than the
Great Pyramid of Egypt.
4. The Eruption
The Mount St. Helens
eruption was the
deadliest volcano
eruption in USA history.
The eruption occurred on
May 18, 1980 and killed
57 people. As well as
that, 200 miles of
highway were destroyed
and 250 homes were
destroyed.
5. The Eruption
(Pt.2)
There was only one lucky thing
that happened in the eruption,
if the eruption had happened
one day later, the death poll
would almost certainly be
doubled. The cost of the
eruption is about 223 million
dollars(Due to reinforcing the
highways and bridges, about
$170 million and the care
centers and visitor centers,
about $50 million).
6. After the
Eruption
Many citizens died during
the Mount St. Helens
eruption. Most of the
deaths, due to the ash
cloud. The ashfall cloud was
40 miles wide and 25 miles
high. Most of the deaths
were direct, but some of the
deaths were indirect. For
example, four people were
killed indirectly in a car
crash, because of the poor
visibility.
7. After the
Eruption
(Pt.2)
As well as all that, the
Toutle River was flooded
from all the melted snow
and ice from the
mountain.About 12 million
feet of lumber were swept
into the river, however
debris dams were made to
help control the sediment
in the rivers.
8. After the
Eruption(Pt.3)
After the eruption, 30
logging trucks, 22
transport vehicles,and 39
railcars were either
damaged permanently or
destroyed, along with 4.7
billion board feet of
timber. Shipping was
stopped on the Colombian
river, and some vessels
were even stranded.
9. Effects on
People
For a limited time, some
people living near the
eruption suffered from
post traumatic stress
syndrome like depression,
troubled sleep,
irritability, and a sense
of being powerless.
10. Tectonic Plate
Boundaries
The plate boundary that created
Mount St. Helens was
destructive. A destructive plate
boundary happens when two or
more plate tectonics move
towards each other and collide.
Volcanoes and earthquakes are
common near this plate boundary
because of pressure and
friction. When the plates move
towards each other, the create
either a subduction zone or a
continental collision.
11. Tectonic Plate
Boundaries
(Pt.2)
It all depends on the plates
involved. In a subduction zone,
the subducting plate(usually the
oceanic plate) will move beneath
the other plate, which can be
either an oceanic or continental
plate. Continental collisions
happen when to continental
plates collide, which creates
large mountain ranges.Mount St.
Helens was part of the
subduction zone process.
12. Why did the
Eruption
Happen?
The 1980 eruption of Mount St.
Helens was caused because of the
North American Continental plate
and the Juan De Fuca Oceanic
Plate.When the two plates moved
together, the oceanic plate went
under the continental because
the oceanic is much heavier. The
temperatures rose, due to magma
and friction, and it caused the
crust to melt, adding to the
existing magma.
13. Why did the
Eruption
Happen(Pt.2)
Because of the melting, bubble
gases were produced, which made
the magma rise closer towards the
surface. The pressure was immense,
and it triggered a 5.1 magnitude
earthquake.The earthquake caused a
vast bulge on volcano to
collapse,and create a debris
avalanche. This released the
pressure on Mount St. Helens,
causing gas and steam to be
explosively expelled, making the
famous eruption.
14. Is Mount St.
Helens related to
the Earth’s Crust?
Mount St. Helens is tied in
with the Earth’s
crust.First of all, Mount
St. Helens erupted because
of the Earth’s crust. The
Earth’s crust is made up of
plates, which move to cause
friction, and eventually
cause volcanoes and
earthquakes to be
triggered.
