Locations at risk from tectonic hazards

Question 1

Seismic hazards

Answer 1

when rocks under the surface come under such stress that they break and become displaced

Question 2

Volcanic hazards

Answer 2

associated with eruption events

Question 3

Intra-plate earthquakes

Answer 3

earthquakes in the middle or interior of tectonic plates

Question 4

Volcano

Answer 4

a landform that develops around a weakness in the earth’s crust from which molten magma, volcanic rock, and gases are ejected or excruded

Question 5

Plate tectonics

Answer 5

theory developed more than 60 years ago to explain the large-scale movements of the lithosphere

Question 6

Lithosphere

Answer 6

the surface layer of the Earth is a rigid outer shell composed of the crust and upper mantle

Question 7

Subduction zones

Answer 7

broad areas where two plates are moving together

Question 8

Locked fault

Answer 8

a fault that is not slipping because the frictional resistance on the fault is greater than the sheer stress across the fault, that is, it is stuck

Question 9

Hypocentre

Answer 9

the ‘focus’ point within the ground where the strain energy of the earthquake stored in the rock is first released, distance between this and the epicentre on the surface is called the focal length

Question 10

Soil liquefaction

Answer 10

the process by which water-saturated material can temporarily lose normal strength and behave like a liquid under the pressure of strong shaking

Question 11

Intensity

Answer 11

a measure of the ground shaking

Question 12

Magnitude

Answer 12

the magnitude of an earthquake is related to the amount of movement, or displacement, in the fault, which is in turn a measure of energy release

Question 13

Epicentre

Answer 13

the location on the earth’s surface that is directly above the earthquake focus

Question 14

Tsunami

Answer 14

tsunamis are initiated by undersea earthquakes, landslides, slumps and, sometimes, volcanic eruptions