the challenge of natural hazards Flashcards
(33 cards)
1
Q
what is a natural hazard
A
a natural event that threatens people or has the potential to cause damage, destruction and death
2
Q
what are the four types of natural hazards
+ examples
A
- atmospheric hazards ( made by movement of air and water in the air) e.g tropical storms, lightning ,drought , tornadoes
-terrestrial / geological ( made by tectonic plates )e.g earthquake, tsunami, volcano, landslide - water based ( made by river , seas , oceans) e.g flooding
-biological (threat to health) e.g virus , bacteria
3
Q
factors affecting hazard risk
A
magnitude, location, time, wealth, education, frequency, natural factors, population density
4
Q
what is the plates tectonic theory
A
the theory that the earths crust is broken up into plates due to the convection currents in the mantle
5
Q
characteristics of contental and oceanic crust
A
continental :
older , thicker , less dense , cant sink ,cant be destroyed
oceanic :
younger, thinner, more dense, can sink, can be destroyed
6
Q
what is the distribution of earthquakes and volcanoes like
A
occur in linear patterns along plate margins,
pacific ring of fire
7
Q
what is a constructive plate boundary + how do earthquakes and volcanoes form here
A
- two oceanic plates moving away from each other
- this allows new land to be created
- volcano : the plates move apart, magma rises through the cracks in the earths surface , a shield volcano forms
- earthquakes : as plates move apart tension is formed ( as movement is not smooth), tension is released by sending shock waves
8
Q
what is a subduction destructive plate boundary + how do earthquakes and volcanoes form
A
- an oceanic and continental plate move towards each other, the denser oceanic plate subducts underneath to continental plate
- volcano : as the oceanic plate subducts it is melted and formed into magma, the magma rises through the cracks, a
composite volcano forms - earthquake : one of the plates gets stuck whilst its subducting another, movement is not smooth, tension builds, as the plates slip past each other tension is released by shock waves
9
Q
what is a destructive collision plate margin + how do earthquake form
A
- two continental plates move towards each other , neither plate sinks as they have the same density and the crust is folded to make fold mountains
- earthquake : as the plates move towards each other the movement isnt smooth, tension builds, released through shock waves
10
Q
what is a conservative plate margin and how do earthquakes form
A
- two plates ( any type of crust ) move past each other in different directions or same directions but different speeds
-plates get stuck as they move past each other, tension builds, tension is released in seismic waves
11
Q
primary effects of tectonic hazard
A
- injury and death
-buildings, property and farmland are destroyed
-communications and public services ( transport, electricity , telephones) disrupted
12
Q
secondary effects of tectonic hazard
A
- tsunami
- shortages of drinking water, food and shelter
-social problems from family loss and stress - fires from burst gas pipes
-spread of disease from contaminated water or dead bodies
-economic problems from cost of rebuilding and the loss of tourism and factories
13
Q
immediate responses of a tectonic hazard
A
- evacuation from areas
-emergency services deployed
-international aid sent e.g tents, bottled water, medical supplies
14
Q
long term responses for a tectonic hazard
A
- rebuilding settlements and infrastructure such as roads
- redeveloping economic activities that were affected e.g farming and tourism
15
Q
nepal earthhquake - key facts ( date, magnitude, epicentre, wealth)
A
- 25th april 2015
- 7.9
- 80 km to kathmandu ( the capital)
- LIC and ranked 109th in GDP
16
Q
nepal earthquake - primary effects
A
- 9000 killed
- 20,000 injured
- 70,000 schools damaged
- 50% of shops destroyed
17
Q
nepal earthquake - secondary effects
A
- 3 million homeless
- avalanches on mt everest killed 19 ( the greatest loss of life here ) and in langtang region 250 went missing
- a landslide blocked the kali gandaki river, many people were evacuated in case of family
18
Q
nepal earthquake - immediate responses
A
- overseas aid including NGOs, Oxfam aid from the uk, india, china
- 300,000 people migrated from kathmandu for shelter and support from family friends
-social media and satelites used to map damaged areas
19
Q
nepal earthquake - long term responses
A
- 7000 schools rebuilt or repaired
- repairs to everest base camp by august 2015 new routes were established
- thousands of homeless people were rehoused
20
Q
christchurch earthquake - key points ( date , magnitude ,
A
21
Q
christchurch - key facts ( date, magnitude, epi centre, wealth )
A
- 22nd febuary 2011
- 6.3
- 10 km south east of christchurch
- HIC ranked 53rd in GDP
22
Q
christchurch primary effects
A
- 181 people killed
- 2000 people injured
- 100,000 homes damaged
- 6 storey canterbury television building collapsed killing 85 people
23
Q
christchurch secondary effects
A
- cost of reconstruction was 11 billion US$
- christchurch could not host the fifth rugby world cup
- 10,000 people migrated out of christchurch
24
Q
christchurch immediate responses
A
- the military was mobilised to help the rescue effort and 300 Australians police officers were flown in
- fire and ambulance crews and other rescue services searched for survivors
25
christchurch long term responses
- water and sewage were restored in the city by august 2011
- government set up the ' canterbury earthquake recovery authority' to coordinate the reconstruction of christchurch which costed £13 billion
- city divided up into 4 zones :
red zones - (worst affected areas close to the inner city)
orange zones - (10,000 residential homes)
green zone ( 100,000 homes )
white zone ( central business district )
26
reasons why people live in areas at risk from a tectonic hazard
- energy ( geothermal energy can be made by using the steam from underground that's been heated by magma. this can be used to drive turbines to produce electricity ) e.g iceland volcanoes has cheap geothermal power (20% of all its energy)
- farming ( volcanic areas often contain the most mineral rich soil thats very beneficial to farming ) e.g italy where they have crops like olives, vines and nuts/fruit
- tourism ( volcanoes attract visitors - help the local economy and provide a source of income )
- scientific research ( to monitor and asses any volcanic risk )
27
how does monitoring help reduce the risks of earthquakes and volcanoes
- volcanoes can be monitored by :
remote sensing, seismicity, ground deformation, geophysical measurements
- earthquakes usually occur without warning thereofre can be difficult to monitor
28
how does monitoring help reduce the risks of earthquakes and volcanoes
- volcanoes can be monitored by :
tiltmeters, GPS and check gas levels to monitor changes before an eruption. Thermal heat sensors and seismometers can observe temperature changes and earth movements
- earthquakes usually occur without warning therefore can be difficult to monitor
29
how does prediction help reduce the risks of earthquakes and volcanoes
- volcanoes :
monitoring the movement of tectonic plates + changes in the surface of the volcano, scientists can forecast the likelihood of a volcanic eruption
- earthquakes :
difficult to predict but scientists can study historical records to identify high risk areas as they are likely to return periods
30
how does protection help reduce the risks of earthquakes and volcanoes
- volcanoes :
embarkments, explosives or concrete blocks can be used to divert lava flow
- earthquakes :
building earthquake proof buildings (shock absorbers, rolling weights, automatic shutters )
31
how does planning help reduce the risks of earthquakes and volcanoes
- volcanoes :
evacuation plans, hazards maps to show areas likely to be affected
- earthquake :
earthquake drills to educate people how to react and maps to show high value lands like hospitals or reservoirs that can be protected
32
what are the three cells of the earth starting from the equator
hadley cell
ferrel cell
polar cell
33
what is global atmospheric circulation
the worldwide system of winds which transports heat from tropical to polar latitudes
