Seismic Hazards

Question 1

What is an earthquake?

Answer 1

At plate margins, where plates are travelling in different directions, stress can build up. When the pressure - resulting from a build-up of friction - is released, a series of tremors or earthquakes can be felt.

Question 2

Spacial distribution of earthquakes
DESTRUCTIVE PLATE MARGINS

Answer 2

Earthquakes here can occur at depth associated by subduction. Earthquakes that occur here are very powerful, can take place under the sea causing tsunami

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Question 3

Spacial distribution of earthquakes
COSTRUCTIVE PLATE MARGINS

Answer 3

Earthquakes here tend to be shallow and less powerfull. Assosiated with tensional forces in the crust and occur along mid oceanic ridges away from large populations.

Question 4

Spacial distribution of earthquakes
CONSERVATIVE PLATE MARGINS

Answer 4

Earthquakes here tend to be shallow but very powerful with severe damage. Caused by continental plates dragging past each other

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Question 5

Liquefraction

Answer 5

During an earthquake shaking causes solid particles to move. In liquid conditions, such as below the water table, this causes a loss of shear strength as the particles lose contact with each other.
Therefore, the soil behaves as a liquid, losing the ahility to support its own weight and building sink or even colapse. On a slope, it causes the soil to move down hill.

Infastructure can colapse, people in or around can be in danger or injury or death.