Hazards Generated By Seismic Activity

Question 1

Earthquake

Answer 1

Release of pressure built up in the earth’s crust

Question 2

Focus

Answer 2

Place in the ground where the earthquake happens

Question 3

Epicentre

Answer 3

Place directly above the focus on the ground where the earthquake is most felt

Question 4

Main places found

Answer 4

Mid ocean ridges

Ocean trenches and island arcs

Collision zones

Conservative plate boundaries

Question 5

Seismic waves

Answer 5

Primary (P waves) - fast travelling, low frequency

Secondary (S waves) - half the speed of p waves, high-frequency

Surface waves (L waves) - slowest, low-frequency, outer crust only

Question 6

Focus definitions

Answer 6

Shallow - 0-70km, very common

Deep - 70-700km, poorly understood

Question 7

Richter scale

Answer 7

Developed in 1935

Logartithmic scale

No upper limit - largest ever = 9.5

Question 8

Mercalli scale

Answer 8

Qualitative

Impacts felt/seen by people

Question 9

Moment magnitude scale

Answer 9

Energy released in the moment

only used for large earthquakes

Question 10

Earthquake land forms

Answer 10

Rift valleys

Fold mountains

Question 11

Earthquake hazards

Answer 11

Ground shaking & displacement

Liquefaction

Tsunamis