Mt. St. Helens

Revision notes

HideShow resource information
  • Created by: vyvyan
  • Created on: 04-10-11 20:45
Preview of Mt. St. Helens

First 393 words of the document:

Vyvyan Kaye de Guzman
Mount St. Helens (not part of the A2 case study because all case studies
must be <30 years)
Located in Southwest Washington, United States
Remained dormant for 123 years.
An active stratovolcano/ composite volcano
Major Eruption on the 18th of May 1980- triggered by 5.1 earthquake
centered beneath the mountain.
Before eruption- 9,677 feet. After eruption- 8,363 feet where 1,314 feet
was removed by the May 1980 eruption.
Area around the volcano was densely covered by forest with some
residents nearby.
Before eruption- it was nearly transformed into a national park.
On 20th March 1980 earthquake of 4.0 was recorded and scientist began
to monitor the volcanic activity by changes in seismicity, ground
deformation, remote sensing, geophysical measurements, gas and
27th of March there was small eruption of steam + gas.
The following May, a huge bulge appeared on the north side of the
volcano, which grew 6ft/day.
People didn't realize the danger and the volcanic activity before the
major eruption became a public attraction to the public and the media.
Scientist continually informed the public though media about the
danger the volcano can exhibit and early evacuations where made to
nearby areas but some people didn't evacuate as they didn't believe that
an eruption is possible.
Social impacts:
57 people were killed as a result of the eruption. Mostly volcanologist
and media reporters who were monitoring the volcanic activity that
21 bodies were never recovered from the blast zone.
People were displaced from their homes and evacuated.
People became vulnerable from poisonous gases eg. sulfur dioxide.
Evacuation became easy as there is only a low density of population in
the danger zone.
Environmental Impacts:
The unique lateral blast was so deadly with megatons of thermal energy
that blasted the north side of Mount St. Helens destroying 100-year-old
trees like toothpicks stripping the forest surrounding the area.
A crater of 3km long and 0.5km deep was created on the north-facing
slope of the mountain.
Pyroclastic flows from the eruption covered 6 square miles of land
which temperatures of nearing 1,300 degrees this destroyed habitats
and rich woodlands.

Other pages in this set

Page 2

Preview of page 2

Here's a taster:

Vyvyan Kaye de Guzman
Massive ash cloud of volcanic materials rise 80,000 feet in 15 minutes,
which reached the earth's atmosphere and may circle the earth for many
years. This will affect the earth's global temperature.
The earthquake that triggered the landslide of the lava dome caused a
landslide of hot mud, rock and ice (melted by the high temperature
Vegetation 21 km of the volcano was damaged.
The landslide released a huge amount of pressure, which worsen the
eruption.…read more


No comments have yet been made

Similar Geography resources:

See all Geography resources »See all resources »