Transcript Mt St Helens eruption 1980

Mt St Helen’s Eruption (May 1980)
Mt St Helens
located on the ‘Ring
of Fire’
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Mt St Helens - Causes of the Eruption
Juan de Fuca plate
North American Plate
Which is the oceanic plate?
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Mt St Helens
Consequences of the Eruption
mudflows 200m
thick in the
upper Toutle
valleys
Toutle
N
O
10km
deadly cloud of
hot ash, dust,
52000 ha of trees rocks and gas
flattened in this travelling at
area
120km/hour
Area of total
destruction
Spirit
Lake
North
Toutle
Mt St Helens
Portland –
harbour
blocked
South Toutle
mudflows
heat melts snow
creating mudflows in
all the major river
valleys
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Mt St Helens eruption
Short term responses
Long term responses
A red zone was set up around the
volcano to restrict access.
Schools in other volcanic areas of the
Rockies prepare for eruptions by
having ‘lahar drills’.
2000 residents told to evacuate.
One refused to leave his home and
he stayed with his 16 cats and 18
racoons.
Scientists learned a lot about
volcanoes from the eruption and have
been studying how plant life has
returned to the area.
Roads were closed to reduce the
number of people wishing to see
smoke and ash coming from the
crater.
Rebuilding of housing, railways and
roads that were destroyed.
People were told to stay indoors
and wear gauze masks.
The ash which fell was gathered up
and heated in kilns before being
molded into 'Genuine Mt St. Helens
Ash Trays'!
Thousands of lives were
undoubtedly saved by evacuating
and closing the area.
Replanting by the Forest Service has
helped vegetation return to the area,
but steeper slopes remain bare.
Why do people live in volcanic areas?
This lava is weathered
(broken down) to form a
fertile soil
Can you think of any other reasons?
Tourists are attracted to
areas of volcanic activity
Geothermal energy
(heat from the earth)
can be produced in
many volcanic areas
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