Mount St

Mount St. Helens

Map showing the location of Mount Saint Helens
Description of the eruption
Magma started flowing into Mount St. Helens in the late winter and early spring of 1980. By May 18, the bulge on the north side of the volcano had likely reached the point where it was unstable, and was creeping faster toward failure. Then there was a magnitude 5+ earthquake which was followed by an avalanche, which unloaded the pressure at the top of the volcano by removing the bulge. This short pressure release allowed hot water in the system to switch to steam, which grew explosively, starting a hot water blast directed laterally through the landslide scar mark . The upper part of the volcano was blown off by force , the pressure decreased on the system of magma beneath the volcano. A wave of decreasing pressure down the volcanic vent to the subsurface magma chamber, which then began to rise, form bubbles , and erupt explosively which started an eruption which was 9 hours long.
List of Damages caused by this eruption
There was a river that was flooded called The Toutle River. It had melting snow and ice from the mountain. 8 eight bridges were destroyed
200 homes were either destroyed or damaged.

Thirty logging trucks, 22 transport vehicles, and 39 railcars were either damaged of destroyed from the molten lava.

Shipping was stopped on the Columbia River and some vessels were stranded
In eastern Washington, falling ash stranded 5,000 motorists ash had to be cleared from roadways and highways.

For a short period of time, some people living near the eruption suffered from post traumatic stress syndrome, depression, troubled sleep and irritability .

There were 4.7 billion board feet of timber which were damaged or destroyed.

Volcanic eruptions

Name: Richards, R
Form: 3A3
Date: Thursday 18th January, 2018
Subject: Geography
Topic: Plate Tectonics