Natural Hazards - Theory

Question 1

Characteristics of Oceanic Crust (Name all 4)

Answer 1

200m years old, very dense, can sink, renewable and can be destroyed

Question 2

Continental Crust (Name all 4)

Answer 2

<1500m years old (older), less dense, can’t sink, can’t be renewed or destroyed

Question 3

Hazards caused by constructive plate boundaries?

Answer 3

Gentle volcanic and seismic activity, SHIELD VOLCANOES, MID-ATLANTIC RIDGE

Question 4

Hazards caused by destructive SUBDUCTION plate margins:

Answer 4

Volcanic activity, earthquakes, COMPOSITE volcanoes PHILIPPINE PLATE

Question 5

Hazards caused by destructive COLLISION plate margins:

Answer 5

Earthquake activity, fold mountains HIMALAYAS (EURASIAN)

Question 6

Hazards found at conservative plate margins:

Answer 6

Earthquake activity - SAN ANDREAS FAULT

Question 7

Primary effects of a tectonic hazard:

Answer 7

Immediate loss of life, damage to services, damage to buildings, transport damaged

Question 8

Secondary effects of a tectonic hazard:

Answer 8

Tsunami, shortages of vital supplies, emotional grief, spread of disease from damaged water, economic issues

Question 9

Immediate responses from tectonic hazards:

Answer 9

Evacuation from areas affected, international aid sent

Question 10

Long term responses to tectonic hazards:

Answer 10

Rebuilding infrastructure and settlements, redeveloping areas

Question 11

Mitigation methods?

Answer 11

Monitoring, prediction, protection, planning

Question 12

How monitoring works for hazards -

Answer 12

Volcanoes - changes in ground shapes by laser beams, satellites detect changes in heat
Earthquakes - change in water pressure, difficult to prove

Question 13

How prediction works for hazards -

Answer 13

Volcanoes - none

Earthquakes - Historical predictions used to identify locations at risk

Question 14

How protection works for hazards -

Answer 14

Volcanoes - lava flow diversions, earth embankments

Earthquakes - buildings constructed to resist shaking, earthquake drills

Question 15

How planning works for hazards -

Answer 15

Volcanoes - predicting areas likely to be affected, restricting land uses and making evac plans
Earthquakes - predicting risk areas, formulating evac plans

Question 16

What causes the movement of tectonic plates?

Answer 16

Convection currents in the mantle

Question 17

How do convection currents work?

Answer 17

As thermal energy rises from the core, this reaches the mantle and upon impact with it moves outwards, causing the mantle to move, dragging oceanic + continental crust with it