4.1 Tsunami

Question 1

What can cause a tsunami

Answer 1

Tsunamis are the displacement of large volumes of water triggered by certain events eg:
1 faults - vertical displacement
2 meteorites
3 volcanic activity- caldera collapse or pyroclastic flow into water
4 landslides

Question 2

How do faults cause tsunamis

Answer 2

1 tectonic - normal or reverse faults will vertically displace the water column to create tsunami
2 the build - the water column collapses sending waves radiating in all directions
3 travel - in deep sea waves barely noticeable; low amplitude, long wavelength
4 approach:
a) waves slow due to increase friction approaching land
b) waves behind still travelling 100s/km/h and catch up
c) creates tsunami, wall of water eg 10m high
5 impact - travels long distance inland destroying everything in its path due to the long wavelength

Question 3

How do you manage tsunamis

Answer 3

1. Tsunami warning system -
   A) Monitoring when earthquakes occur
   B) buoys in ocean connected to satellites can track tsunami progress
2. Build coastal defences eg seawalls, drainage channels, coastal forests
3. Buildings at angle to the coast to divert wave power