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A-Level Geography > Earthquakes > Flashcards

Flashcards in Earthquakes Deck (21)
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1

What is the focus?

The point of fracture, where energy is suddenly released

2

What is the epicentre?

Directly above the focus

3

What are faults?

Pressure builds and cracks along the crust fractures

4

What are the body waves?

Waves that move through the earth's surface

5

What does a primary wave move through?

Solids and liquids

6

What does a secondary wave move through?

Solids

7

How do primary waves move?

Compresses then expands

8

How do secondary waves move?

Vertical movement

9

What are surface waves?

Waves that travel through the surface of the crust

10

What are the body waves?

Primary and secondary waves

11

What are the surface waves?

Love and rayleigh waves

12

How is magnitude measured?

Moment magnitude scale

13

What is magnitude?

The amount of energy released at the epicentre

14

What is intensity?

The earthquakes effect on people, structures and natural environment

15

What scale does the moment magnitude use?

1-10log

16

How is intensity measured?

Mercalli intensity scale

17

What scale does the mercalli intensity use?

I - X1

18

What are the primary effects of earthquakes?

Ground shaking- causes infrastructure to collapse
Crustal fracturing- seismic energy causes the crust to crack at surface

19

What are the secondary effects of earthquakes?

Tsunami- submarine earthquake
Fire- power line + gas pipes break
Liquefaction- violent shaking leads to surface rocks losing strength
Landslides+ avalanches- ground shakes and places stress on slopes which leads to landslides

20

What is theory one of intra plate earthquakes?

Stress builds along ancient faults causing them to activate again

21

What is theory two of intra plate earthquakes?

Crust that was once weighed down by glaciers is rebounding from mantle triggering earthquakes