Earthquakes

Question 1

When a weak are of the crust breaks…

Answer 1

Seismic waves deep in crust are sent to surface

Question 2

Epicenter

Answer 2

Point on surface immediately above focus

Question 3

Occur along…

Answer 3

Plate margins. Plates move, friction, pressure builds up, pressure is released = earthquake

Question 4

Focus

Answer 4

Point where earthquake starts

Question 5

Main zones

Answer 5

• where mid oceanic ridges are forming new crust
• around pacific plate, closely matching “Ring of Fire”
• collision line between African, Indian and Eurasian plate

Question 6

Shallow

Answer 6

0-70km below

Question 7

Intermediate

Answer 7

70-300 km below

Question 8

Deep

Answer 8

300+ km below

Question 9

Divergent

Answer 9

• pulling apart
• common
• small in magnitude
• shallow occurring at crest of oceanic ridge/rift valley

Question 10

Convergent

Answer 10

• subduction zones
• all three types along subduction zones of Pacific Ocean
• most widespread + intense activity

Question 11

Faults

Answer 11

• Where sections of the earth move past each other, tears and breaks in crust
• vary in size

Question 12

P Waves

Answer 12

• little displacement
• fast moving
• push and pull, stretch and squeeze alternately

Question 13

S Waves

Answer 13

• follow P waves
• strong reading on Seismograph
• slower
• more damage
• up and down

Question 14

Aftershock

Answer 14

• smaller earthquake that follows primary earthquake

* rocks settle into new positions within crust

Question 15

Richter scale

Answer 15

• reflects amount of energy released by earthquake
• based on size of seismic waves
• x10

Question 16

Effects of Earthquakes

Answer 16

• violent ground movement
• collapse of buildings, bridges
• tsunamis and landslides
• loss of basic services
• loss of basic infrastructure
• loss of electricity and water
• drainage and sewerage systems affected
• fires

Question 17

Skyscraper modification

Answer 17

• wide base leading up to thinner point, channel vibrations up, does not sway
• large scale dampers placed at bottom, absorb vibrations

Question 18

Tsunamis

Answer 18

• happen as a result of earthquake/earth tremor
• natural phenomenon consisting of a series of waves generated when water in a lake or sea is rapidly displaced on a massive scale
• lose energy

Question 19

One way in which…

Answer 19

The earth can relieve pressure caused by moving crustal playes