Transcript Mount St Helens and Nevada Del Ruiz : Living with a Volcano

Mount St Helens and
Nevada Del Ruiz : Living
with a Volcano
By David Satherley
Introduction
• In this project I will
be talking about the
difference in the way
M.E.D.C’s and
L.E.D.C’S cope with
the threat of volcanic
activity. As examples,
I will be using Mt St
Helens and Nevada
Del Ruiz and how
they shocked those
who witnessed them.
Mount St Helens Location
• Mount St Helens is located in the south west region of Washington state
which is about 50 miles north-east of Portland, Oregon. It is in the Cascade
mountain range.
Mount St Helens History
Mount St Helens was named in
1792 in honour of Baron St.
Helens. American Indians of the
Pacific Northwest called
“Louwala Clough” which meant
“smoking mountain”. The
volcano was active in the mid
1800’s , but most people in this
century did not see it as
something evil but very
beautiful- the forest on it and
around the base was filled with
wildlife . There was also a spirit
lake which was excellent for
fishing.
St Helens Environmental ImpactCountryside
•
•
Despite the money and technology,
Mount St Helens eruption still had
a devastating impact. In a landslide
that covered 24 square miles, the
was a huge loss of wildlife, roads
and bridges were destroyed and
Spirit Lake was covered. 200
houses and
Cabins were lost, tens of thousands
of acres of prime forest were
destroyed. 185 miles of highway
were destroyed. Many animals deer, elk and bear were killed . This
damage would take years to
recover. Although this was no
where near as bad as Nevada Del
Ruiz’s devastation.
Mount St Helens Environmental
Impact - Humans
• 57 people died, loss of wildlife meant loss
of hunting, Means of transport were
destroyed - roads, bridges and cars. Homes
were lost or flooded. No Spirit Lake for
fishing and boating. No cross-country
skiing. No lodges or camping grounds; no
nature trails. Logging equipment and
industry was devastated. Jobs lost, and
crops annihilated .
Nevada Del Ruiz Location
• Nevada Del Ruiz is located in the Andes
Mountains, in Columbia, South America.
Nevada Del Ruiz History
• The Colombian volcano has a
long history of creating deadly
lahars from relatively small
eruptions. In 1595, a lahar
swept down from it’s peak
killing 636 people. In 1845,
another lahar flooded the same
area, this time killing over 1000
people. On the solidified mud
of the lahar, was built the town
of Armero. It grew to a
population of 27,000 people,
but unfortunately history
decided to repeat itself in the
same place yet again but this
time with devastating effects.
Nevada Del Ruiz Environmental
Impact- Country
• Nevada Del Ruiz is covered by a glacier. The
small eruption melted part of this ice, and the
enormous amounts of water that produced a
mudflow (lahar) that covered the town of Armero
which was located in the valley below the
volcano. The torrents of debris (the lahars) poured
down the mountainside , stretching up to 40
metres thick and as fast as 50 kph. Although
higher ground wasn’t so much effected, Armero
lay directly in it’s path.
Nevada Del Ruiz Environmental
Impact- Humans
• The impact of the 1985 eruption was horrific.
22,000 people were killed due to a lahar which
struck the people of Armero . But with proper
planning this tragedy could have been prevented.
Columbia had no monitoring equipment, and no
skilled enough geologists, so it would be
extremely difficult to predict what the volcano was
doing. A group of scientists from abroad did come
to observe the crater, but saw nothing to be
alarmed about. The following morning 22,000
people died because of it.
M.E.D.C’s and L.E.D.C’s
As an M.E.D.C you can see that the surrounding area of
Mount St Helens is much less likely to be threatened by
volcanic activity as much as Nevada Del Ruiz. In their most
recent eruptions, Mount St Helens only cost 57 lives whereas
Nevada Del Ruiz’s eruption took a massive 22,000 lives.
This proves that the technology, is vital for the evacuation
and warning in these situations. But in this L.E.D.C a crucial
discovery was made shortly after the eruption by Bernard
Chouet .
The Discovery
•
After the eruption of 1985 eruption
of Nevada Del Ruiz, volcanologists
tried to figure out a pattern from
the seismographs, in an attempt to
predict volcanic eruptions. They
couldn’t find one though. Then
Bernard Chouet made his discovery
of long period events. This is where
the magma builds up inside the
chamber causing immense
pressure. It produces a long period
earth tremor which can be seen on
the seismograph. The more this
happens in a day, the closer the
eruption will be. Thanks to Chouet,
we now have a rough way of telling
when an eruption is due.
Conclusion
• In coclusion I hope that this project has
shown the difference between a volcano in
an L.E.D.C and one in an M.E.D.C and the
amount of money that is needed to help
prevent these disastrous volcanic events.
Unfortunately an L.E.D.C like Columbia
cannot afford the equipment and may not
have the geologists and volcanologists that
an M.E.D.C such as the U.S.A may have.