1. Mount St. Helens
We are here

2. What Mt. St. Helens looks like now…

3. What Mt. St. Helens used to look like…

4. In 1980 Mt. St Helens erupted

5. What observations can be made about the eruption?
Write Mt St Helens observations on the top half of the front of your folded organizer
Discuss with your table groups the observations you made
Be prepared to share these with the whole class

6. Class Observations - -before erupted stratocone volcano
-5.8 earthquake rumbled volcano right before
-loss of life: bugs, 100’s of species of birds, 57 people, wildlife
-pyroclastic flow, lahar
-1300 ft torn off summit, mile wide crater
-moved lakes
-largest North American eruption in 100 years
-north side collapse
-5.1 earthquake
-huge landslide, ash and steam into the air
-wildlife killed, 57 people died
-ash cloud covered over 100 miles, miles high as well
-spirit lake moved 200 feet up
-explosion heard 100’s of miles away
-rumbling a few weeks before eruption
-pyroclastic flow

7. What are some ideas as to why this eruption happened?
There was an explosive volcanic eruption because…
There was an explosive volcanic eruption because…..
Gases and magma built up inside the mountain, earthquake caused it to be pushed out
Earthquake cause pressure inside to become too much
There was magma and an earthquake
There was plate movement, divergent, causing the eruption
Earthquake triggered landslide
Heat and pressure became too much
Pressure led to plate movement
Plate movement, earthquake, eruption
(per. 1)
There was an explosive volcanic eruption because…
earthquakes and friction caused the eruption
the plates overlap each other and converge and that caused eruption
magma (and maybe ash too) built up and pressure built up , then erupted
pressure/eruption caused earthquake
There was an explosive volcanic eruption because…
massive pressure built up from convergent plates
pressure caused by friction in the earth from spinning, -->heat--> gasses pushing up
earthquake made it crumple and then pressure could release
earthquake casued collapse, which allowed magma to overflow

8. Initial explanations….
This is only the first draft, and we will be making revisions as we learn more about volcanic eruptions
As a table group, use our list of observations and ideas to write an initial explanation to explain why Mt St Helens erupted explosively

10. Class Observations 57 people killed
Eruption went up and out- very big
Huge earthquake, rumbling
Eruption changed the shape of the mountain
Huge ash cloud
Killed a lot of life- 57 people, deer/elk, insects, squirrels, birds, wildlife
Nearby land covered in ash
Avalanche flattened forest, pyroclastic flow
Trees in blast radius got incinerated
Lake turned black
Material moved fast, eruption happened fast
Lake was raised, landslide (per 1.)
57 people killed
Earthquake, landslide, prior to eruption
Wildlife killed
Poisonous gases, hot steam, landslide
Ash went mostly to one side, in one direction
1300 ft of the mountain was blown off
Pyroclastic flow-
Spirit lake was dislocated and smothered- lake bed was raised
Cone shaped and changed shape of the mountain
Really large, went high upto sky, went outward covering ground too