Mount St Helens case study

Question 1

What date did the eruption of Mount St. Helens occur?

Answer 1

May 18, 1980

Question 2

Where is Mount St. Helens located

Answer 2

Located on a destructive plate boundary in Washington county Skamania in the rocky mountains where the Pacific plate is subducted under the North American plate

Question 3

What type of volcanic eruption occurred at Mount St. Helens?

Answer 3

Plinian eruption

Question 4

Fill in the blank: The eruption of Mount St. Helens was preceded by a series of __________.

Answer 4

foreshocks

Question 5

What was the magnitude of the earthquake that triggered the eruption?

Answer 5

5.1

Question 6

How many people died as a result of the eruption?

Answer 6

57

Question 7

True or False: The eruption created a large crater at the summit of Mount St. Helens.

Answer 7

True

Question 8

Located at a __________ zone

Answer 8

subduction

Question 9

How many years since the last eruption

Answer 9

120 years

Question 10

After the first earthquake it was followed by 10 thousand aftershocks, this is incorrect what were they actually

Answer 10

Foreshocks

Question 11

_______ of 150m was found on the side of the volcano

Answer 11

Bulge

Question 12

The date of the second earthquake

Answer 12

May 18th 1980

Question 13

The bulge on the side of Mount St. Helens burst causing what

Answer 13

1. The largest landslide ever recorded (200km/h)
2. A signicant nuée ardente
3. A lahar

Question 14

What was the long term effects of the eruption

Answer 14

1. Made into a national monument
2. Site of a volcanic laboratory
3. Made surrounding soil fertile
4. Wildlife reclaimed the area

Question 15

When the bulge burst it caused the snow and glacial ice to met causing what?

Answer 15

A lahar

Question 16

After the main vent erupted what happened?

Answer 16

A pyroclastic flow buried everything in 10 km radius

Question 17

Mud and debris clogged the river causing what?

Answer 17

Making the river over flow leaving ships stranded and unable to deliver aid

Question 18

What was the short term effects of the eruption

Answer 18

1. 57 people died
2. Infrastructure was destroyed 250 km of roadway, 25km of railway and 27 bridges
3. Thousands of animals and birds were killed and 10 million fish
4. Forestry was burnt down and striped of its foliage, agricultural land was covered in ash and destroyed

Question 19

The date of the first earthquake

Answer 19

Mid-March 1980

Question 20

The magnitude of the first earthquake

Answer 20

4