Natural Hazards

Question 1

Natural Hazards : Tectonic hazards: Natural hazard, disaster and phenomenon’s

Answer 1

• A physical event such as a volcanic eruption that does not affect human beings is a natural phenomenon
• a natural phenomenon that occurs in a populated area is a natural hazard
• A natural hazard that caused unacceptably high fatalities or property damage is a natural disaster

Question 2

Natural Hazards : General hazards: factors affecting hazard risk

Answer 2

1) Physical factors
=> Rock type in an earthquake, shape of the coastline in a tsunami etc…
2) Duration
=> the longer an event goes on for, the more the chances for deaths and property damage. Rescue cannot happen/much more difficult while the event is occuring
3) Frequency
=> Frequent natural hazards are actually less dangerous as the people at risk will have developed coping mechanisms. (i.e. Tokyo gets earthquake each week but one in London would flatten the city)
4) Population density and distribution
=> more dense => more people at risk
5) Level of development
=> richer countries will have money and equipment needed for a response/prepared for an event
6) Management
=>3 Ps
7) Education
=> educated about drills etc
8) religious and cultural norms
=> some areas with more fatalist mentalities will often suffer higher death counts.

Question 3

Natural Hazards : Tectonic hazards: Distribution of earthquakes and volcanos

Answer 3

-Destructive plate margin
=> Earthquakes & fold mountains
-Constructive plate margin
=> volcanos only (mostly shield)
-Conservative plate margin
=> Earthquake only
Lots of earthquakes and volcanos on the ring of fire

Question 4

Natural Hazards : Reducing the risk from Tectonic hazards: Monitoring, Prediction, Planning and Protection Def

Answer 4

Monitoring : using scientific equipment to detect early warning signs of events
Prediction : using historical evidence and monitoring to predict when a tectonic event may happen
Planning : Identifying and avoiding places most at risk and making plans for if a hazard were to occur
Protection : Designing buildings that withstand tectonic events

Question 5

Natural Hazards : Reducing the risk from Tectonic hazards: How it is done for Volcanos

Answer 5

Monitoring : Remote sensing uses satellites to detect heat and changes to the volcanos shape
-Seismographs detect mini earthquakes leading to an erruption
-Hydrology => volcanos emit gasses prior to an eruption which can be detected in water

Prediction : cannot be done on volcanos
Protection : diverting of lava away from settlements
Planning : Hazard maps show areas to avoid development and building evacuation routes

Question 6

Natural Hazards : Reducing the risk from Tectonic hazards: How it is done for Earthquakes

Answer 6

Monitoring : Ground deformation
-foreshocks
-changes in water pressure are monitored, but in general earthquakes are difficult to monitor
Prediction : Historical data can be used to predict future earthquake locations to great accuracy. (when earthquakes occur, stresses get passed along the fault lines)
Protection : Steel frame buildings are more resistant.
-Computer controlled weights on the top of the roof reduce movement.
-Shorter buildings
-deeper foundations
-Shock absorbers
Planning : Early warning systems (DARTII-japan)
=> DART stops trains, factory lines, elevators, workers