Natural Hazards

Created by

Reyah Riz

Cards (41)

Natural hazard
Natural event or process which could cause loss of life or damage to property + creates disruption to human activity
Atomospheric natural hazards
Tropical storms, Climate change, Extreme hot or cold
Geophysical natural hazards
Volcanoes, earthquakes, tsunamis
Hydrological natural hazards
flooding, landslides, drought
Factors affecting risk
Population density, deforestation, wealth, climate change
Population density
Areas at risk are densely populated, more people the more people at risk
deforestation
destroying large areas can increase risk of flooding, landslide and drought
Wealth
LICs are at more risk as more people are living in slums. HIC's can cope with disaster
Climate change
Rising temperatures mean more drought. Wetter seasons increase flood chance
Layers of the earth
Inner core, Outer core, Mantle, Upper mantle, Oceanic crust, continental crust
oceanic crust
thin (5-10km), it carries water and is made of basalt. Newer (less than 200mil). Denser so it can sink
Continental crust
thick (100km), it carries land and is made of granite. Older (1500mil) and is less dense
Tectonic plates
Name the plates
A) Eurasion plate
B) African plate
C) Antartic plate
D) Pacific plate
E) Nazca
F) North American
G) Pacific
H) Australian
I) carribean
Continental drift
Plate tectonics formed
Earthquakes
Found along plate margins in narrow belts. E.g. Ring of fire. Anomaly is Hawain Island - hot spot in pacific plate
Volcanoes
Formed mainly at constructive and destructive plate margins
Destructive (Ocean vs continental) 
Two plates are moving together

The denser oceanic plate is subducted beneath the lighter continental layer

Pressure is released to form earthquakes

The magma rises through continental plates to form volcanoes
Ring of fire
Two continental plates collide, and neither subducts
Forms fold mountains which forms earthquakes at collision margins
Constructive
Two plates move apart
Magma rises as plates separate
Magma cools, hardens and forms new land
Shield volcanoes form
The movement of plates forms earthquakes
Conservative
Two plates move past each other at diff speeds
As plates move friction occurs
As pressure is released earthquakes form
No volcanoes are formed

E.g) San Andreas Fault - pacific plate and north american plate
measuring earthquakes
Measured using the Richter scale and Mercalli intensity scale

epicentre
Isoseismal lines
Focus
seismic waves
measured with a seismometer
Primary effects of earthquakes
Buildings destroyed
People injured
Homelessness
communication and transport cut off
Secondary effects of earthquakes
Disease spread form sanitation
Aid needed
Landslides
Tsunamis
Immediate responses of earthquakes
Conduct rescue searches
Extinguish fires
recover dead bodies
Temporary shelters
Temporary supply of food+ water
Long-term responses to earthquakes
Rehouse homeless
Repair buildings
Restore water, energy, gas
Improve building designs
Nepal Earthquake
LIC
7.9 on Richter scale
25/04/15
Destructive plate (Indo Australian and eurasion)
80km from kathmmandu
Primary Effect of Nepal Earthquake
9000 killed + 20000 injured
8 million affected
3 million homeless
7000 schools + 600000 homes destroyed
50% of shops have gone
Power and water supplies were destroyed
1.4 million needed shelter
costed 5 billion
Secondary Effect of Nepal Earthquake
Landslides and avalanches from ground shaking
Mt Everest avalanche killed 19 people
Landslide blocked rivers
250 people missing
No tsunamis as on land
Tourism rates fell
Immediate Responses of the Nepal Earthquake
International aid from UK, India, china - £87 million raised
Helicopters used for rescue
300000 fled from Kathmandu
Field hospitals set up
Social media used as communication
Long-term Responses to the Nepal Earthquake
3/4 of homes repaired by 2019
buildings were earthquake proofed
Landslide cleared and roads repaired
7000 schools re built
tourism boosted
Earthquake education taught in school
June 2015, conference hosted for financial aid
Chile earthquake 
HIC
8.8 Richter
27/02/10
Destructive plate (Nazca and South American)
By sea so tsunamis occured
Primary Effect of the Chile Earthquake
500 killed + 12000 injured
800000 affected
22000 homes + 4500 schools damaged
53 ports and hospitals damaged
Loss of power, communication, electricity
posted 30 billion
Secondary Effect of Chile Earthquake
Landslide - damaged 1500km of road
Tsunami - devastated coastal towns
Fires broke out due to busted pipes
People had to evacuate
Immediate Responses of the Chile Earthquake
Emergency services came quickly
Temporary repairs to Route 5 allowed aid and transport
Temporary shelters
Power and water restored to 90% of homes
60 millions raised
Long term responses of the Chile Earthquake
Set up national housing reconstruction to help 200000 houses
Houses were demolished as it was not safe
Foreign aid was not needed
Took 4 years for chile to recover
reducing tectonic hazards 
Predict - using seismometers to detect movements
Protect - all buildings must be earthquake-proofed
Prepare - evacuation plans in place, emergency supplies
Earthquake resistant buildings
steel frames - sway during earthquake
reinforce lifts - with tension cables
Rubber shock absorbers in foundation
Open areas - where people can assemble
Shutters - over windows to stop pedestrians form being shatterd
Helicopter pad - aid + transport
rolling wights - on roof to counteract shock waves
Earthquake-resistant buildingsin LICs
bamboo used to absorb shock
roof made from reinforced cement
reinforced steel pillars, provide flexibility + strength
Earthquake resistant bridges 
Steel cables attached to the bridge to restrain movement
Concrete walls added to make it more rigid
Covered with steel to keep it from crumbling