Earthquake key terms

Question 1

Earthquake

Answer 1

A short period of intense shaking experienced at the surface of the Earth caused by a slow build up of stress within the rocks due to the crust’s constant movement

Question 2

Focus

Answer 2

The point at which the pressure release of the earthquake occurs, the depth of which influencing the effects
shallow- 0-70km (greatest damage)
intermediate- 70-300km
deep- 300-700km

Question 3

Epicentre

Answer 3

The point above the focus at the Earth’s surface

Question 4

Moment Magnitude Scale

Answer 4

A scale that measures the size of an earthquake in terms of the energy released (MW)- a logorithmic scale

Question 5

Mercalli scale

Answer 5

A qualitative scale measuring an earthquake in terms of the strength of the shaking produced, the intensity of the event, and its impact

Question 6

Ground rupture

Answer 6

The visible breaking and displacement of the Earth’s surface, typically along a fault line

Question 7

Liquefaction

Answer 7

Soils with a high water content lose their mechanical strength when shaken, causing them to behave like a liquid and possibly cause mudflows

Question 8

Seismic gap

Answer 8

A segment of a major fault known to produce significant earthquakes that has not slipped in an unusually long time, compared with other segments along the same fracture

Question 9

Retrofitting

Answer 9

The addition of new technology to older systems in order to become more resistant and resilient to the damaging effects of hazards

Question 10

Aseismic design

Answer 10

Designs meant to withstand earthquakes