1. Volcanoes – Friend or Foe?
What are the effects of volcanoes on man and the environment?

2. located on the ‘Ring of Fire’
Mt St Helen’s Eruption (May 1980)
Mt St Helens
located on the ‘Ring of Fire’
Mark Mt St Helens on your map of where volcanoes and earthquakes are located.

3. Mt St Helens - Causes of the Eruption
North American Plate
Juan de Fuca plate
Which is the oceanic plate?
Task 2: Describe how a volcano is created in 2 sentences.

4. Mt St Helens - The Eruption
Animation showing the Mt St Helen’s eruption with text

5. Video: Mt St Helens
Make notes about the effects of this volcanic eruption on people.

6. Mt St Helens
AFTER
BEFORE

7. Consequences of the Eruption
Mt St Helens
Consequences of the Eruption N O
10km
Interactive map
Redrawn map, showing compass point, scale line, Mt St Helens, North and South Toutle rivers and area of total destruction. Buttons (North Toutle, trees flattened, Portland, Mt St Helens, Spirit Lake, ash cloud) reveal extra information when clicked…eg click on North Toutle button and ‘mudflows 200m thick in the upper Toutle valleys’ appears

8. What damage did the eruption cause?
Up to 70mm of ash falls across Washington and East Montana…7000 school students have an early Summer vacation due to problems on the roads
Mudflows block and divert rivers.
Damage to crops $175 million
More tourism
Two million birds, animals and fish are killed.
Less tourism
Hot mudflows raise the temperature of the rivers to 30ºC
Communications threatened – railway and road bridges destroyed, Portland harbour blocked
Deer mice, chipmunk, vole, gophers, salamander survive the blast.
60 people die from the eruption.
Gophers, through their tunnelling, mix the soil with the ash. This increases the fertility of the soil.
The post office and Lone Fir Motel shut down in Cougar.
Separate the above into the short term and long term impacts of the eruption.

9. Homework: Due:______
What are the affects of a volcanic eruption on people? Give examples.
Write about 100 words to answer the above question.

10. Homework review:
Hot spot volcanoes - Hawaiian Islands
Active volcanoes
Extinct volcanoes
Hot spot
In the diagram above, why are the volcanoes to the right of the ‘hot spot’ extinct?