Natural Hazards and Disasters

Question 1

Natural Hazard

Answer 1

A natural process that has the potential to affect people

Question 2

Natural disaster

Answer 2

A major natural hazard that causes significant S,E, and E damage to people and the environment

Question 3

vulnerability

Answer 3

The ability to anticipate, cope with, resist and recover from a natural hazard

Question 4

Nepal’s vulnerability and its effects

Answer 4

• Hit densely populated capital
• Poorest countries
• Weak infrastructure and buildings
• Large aftershocks
• Himalayas difficult terrain
• Heavily reliant on tourism

Question 5

Mantle convection

Answer 5

heat (produced by radioactive decay in the mantle) warms up the lower mantle creating convection currents (magma currents moving in circles)

Question 6

Slab Pull

Answer 6

the new oceanic crust at mid-ocean ridges becomes thicker and denser as it cools - sinks and pulls the rest of the plate with it

Question 7

Subduction

Answer 7

The collision between 2 oceanic plates - one subducts (sinks and melts in the mantle - subduction zone)

Question 8

seafloor spreading

Answer 8

mid-ocean ridges are formed when hot magma rises up to the surface and hardens (new crust) - this process pushes tectonic plates apart

Question 9

Paleomagnetism

Answer 9

Evidence of seafloor spreading is gained from the polarity of the rocks on the ocean floor. Iron particles in lava are aligned with the earth’s magnetic field. The polarity of the earth can reverse which creates a magnetic stripe pattern with the seafloor rocks. These striped patterns are mirrored on both sides of the Mid-ocean ridge which proves they were once together

Question 10

DESTRUCTIVE

Oceanic + Continental

Answer 10

deep ocean trenches - oceanic plate subducts

• can lead to folding mountains (crumpled continental)
• deep earthquakes from friction
• melting magma rises due to subduction causing explosive eruptions

Question 11

DESTRUCTIVE

Oceanic + Oceanic

Answer 11

• deep trenches + underwater volcanoes
• creates separate island volcanoes (arcs)
• deep-focus earthquakes (shallow)

Question 12

DESTRUCTIVE

Continental + Continental

Answer 12

Collision margin - high fold mountains (e.g. Himalayas)

shallow focus earthquakes - high severity

Question 13

CONSTRUCTIVE

mid-ocean ridges

Answer 13

underwater mountains

• shallow focus EQ and submarine volcanoes + islands
• occur due to transform faults

Question 14

Rift Valleys

Answer 14

when plates move apart on continents the crust stretches and breaks into a set of parallel cracks. The land between these faults collapses and forms steep-sided valleys

Question 15

conservative margins

Answer 15

plates sliding past each other - major break
powerful earthquakes due to built-up pressure
e.g. san Andreas fault California