Nature And Distrubution

Question 1

Define earthquake

Answer 1

Crust of Earth is mobile there tends to be a slow build up of stress without rocks.

Suddenly released parts of surface experience intense shaking.

Question 2

Focus

Answer 2

Point in which energy releases from within the crust.

Seismic waves travel from here.

Question 3

Epicentre

Answer 3

Point directly above focus on the crust

Question 4

Shallow

Answer 4

0-70

Greatest damage as energy is expended more on to surface.

Account for 75% of all earthquake energy released

Question 5

Intermediate

Answer 5

70-300km

Question 6

Deep

Answer 6

300-700km

Question 7

Where do the vast majority of EQs occur ?

Answer 7

Along plate boundaries.
pacific ring of fire.

Most power at destruction margins where subduction occurs as there is lots of tension/ energy built up here.

Also at conservative margin

Question 8

Eg of earthquakes caused by tectonic plates

Answer 8

Sand Andreas Fault California.

N. America and Pacific plates.

Lots of fractures in crust

Question 9

Where is there a linear line of earthquakes?

Answer 9

Down west side of North American plate.

Down east side of South American plate.

Question 10

Where is there clusters of earthquakes?

Answer 10

South of Eurasian plate.

South west of North American plate

Question 11

Where else do earthquakes occur?

Answer 11

Reactivation of old fault lines

September 2002 EQ occurred in uk midlands.
Epicentre was in Dudley and was 4.8 on Richter scale

Question 12

How can human activity cause EQs ?

Answer 12

Building large reservoirs which puts pressure on underlying rock.

Subsidence is deep mines

Fracking