Mount St. HelensMount St. Helens

The EruptionThe Eruption

Where is Mount St. Where is Mount St. Helens?Helens?

Mt. St Helens is in Washington state 96 miles (154km) south of Seattle and 50 miles (80km) north of Portland, Oregon.

What is Mount st. What is Mount st. HelensHelensMount st Helens is a volcano which Mount st Helens is a volcano which

was dormant for 123 years was dormant for 123 years before it erupted on the morning before it erupted on the morning of May 18of May 18thth 1980. 1980.

                                                                                                                                                       

                                                                                                                                                       

                                                                                                                                                      

                                                                                                                                                       

                                                                                                                                                       

                                                                                                                                                      

What were the effects What were the effects of the eruption?of the eruption?57 people were killed in the blast 57 people were killed in the blast

and the first was a lone and the first was a lone geographer called David A. geographer called David A. Johnston who had been left to Johnston who had been left to monitor Mt. st. Helens stages of monitor Mt. st. Helens stages of eruption.eruption.

How did it happen?How did it happen?

There was a sequence of earthquakes There was a sequence of earthquakes (about 10,000 to be precise) then (about 10,000 to be precise) then the lava started to flow up through the lava started to flow up through the volcano and it met a blockage of the volcano and it met a blockage of old lava that had set so that it was old lava that had set so that it was rock hard the lava diverted its path rock hard the lava diverted its path and it formed a bulge on the side of and it formed a bulge on the side of the mountain and it grew and grew.the mountain and it grew and grew.

Environmental impacts Environmental impacts of the eruptionof the eruptionThe eruption knocked down The eruption knocked down

loads of trees when it struck loads of trees when it struck the forest at over 100 mphthe forest at over 100 mph

It also filled the sky with ash It also filled the sky with ash from the volcano.from the volcano.

Human impactsHuman impacts

People lost lots of money and People lost lots of money and homes during the eruption and homes during the eruption and this caused them to be homeless this caused them to be homeless as they didn’t have a home to go as they didn’t have a home to go to.to.

Business impactsBusiness impacts

The business impacts were that the The business impacts were that the trees people were logging got trees people were logging got knocked down by the blast. knocked down by the blast. Causing them to lose lots of Causing them to lose lots of money and killing several people.money and killing several people.

Mount st HelensMount st HelensBefore After

Why it EruptedWhy it Erupted

The magma in the volcano built up The magma in the volcano built up and it got blocked by the years and it got blocked by the years worth of rock that had built up worth of rock that had built up when the magma cooledwhen the magma cooled

ConclusionConclusion

My conclusion is that mount st My conclusion is that mount st Helens eruption was fatal to Helens eruption was fatal to many living things and would many living things and would change the world forever.change the world forever.