Geography - Natural hazards - Paper 1

physical geography dec- may Year 10

natural event

something that happens naturally ftom the earths systems/process e.g earthquake

natural hazard

when a natural event poses a risk to people and/or property

natural disaster

a natural hazard with a huge impact on people + environment

vulnerable population

a population that doesn’t have the resources to protect or help itself

4 factors that affects the risk of natural hazards

urbanisation

poverty

climate change

farming

how does urbanisation affect the risk of natural hazards

densly populated cities are more at risk than rural areas. fofr example 2010 haiti earthquake demolished the capital port-au-prince and killed 230000 people

how does poverty affect the risk of natural hazards

shortage of housing means people live in more dangerous areas e.g slopes also built with weaker materials than HIC countries for example lima in peru

how does climate change affect the risk of natural hazards

as the world gets warmer the atmosphere has more energy- leads to more intence storms/ hurricanes and cause parts of the world to be more wet and increase floods e.g china or be more drier and have droughts/famines

how does farming affect the risk of natural hazards

e.g river Ganges in Bangladesh. when a river floods it leaves a fertile silt on its floodplain-this is good for farming but can destroy houses. the more people living near a river increase the risk so people should farm and live somewhere else.

what are the 4 layers of the earth inside to outside

inner core, outer core, mantle and crust

is the inner, outer core and mantle solid or liquid

inner core → solid

outer core →liquid

mantle → solid but slows very slowly

what is the upper part of the mantle called

asthenosphere

lithosphere

the upper part of the mantle and crust together form

is broken into lots of fragments called tectonic plates

what are the 2 types of crust and how dense are they

oceanic crust→ 5-10km and is denser

contiental crust →25-100 km thick and is less dense

do tectonic plates flow

yes very slowly around 3-5 cm a year

plate margine/boundary

where 2 plates meet

how many plate margins are there and what are they called

3

constructive, conservative, destructive (2 types subduction, collision)

constructive plate margin- direction of movement,tectonic features and example

direction of movement- 2 plates move away

tectonic features- shallow,small earthquakes + volcanoes with wide base + gentle slopes

example- eurasian + N american plate move away 5cm a year

what happens a tconstructive plate boundary

• upper part of mantle melts + hot molten magma rises

• plates move away- magma rises and cools-forms solid rock- oceanic plate

• new plate might fracture when moved cause earthquakes

• magma doesn’t reach surface but pushes the crust up to form ridge

• magma erupts produces lava that spreads out then solidifies

• on land constructive plate margins form a steep-sided valley (rift valley) where the land drops plates move apart

tectonic plate margin where rising magma adds new material to plates that are moving apart

destructive- collision - plate margin- direction of movement,tectonic features and example

direction of movement- 2 continental plates crash into each other tectonic features- plates collide- form mountains, small earthquakes

example- India- Australian +Eurasian plates form Himalayas

destructive- collision what happens

2 contiental plates collied- can’t sink into the mantle

compression forces plates to collide + form new mountains

destructive- subduction - plate margin- direction of movement,tectonic features and example

direction of movement- oceanic + continental plates move towards each other + collide

tectonic features- mountains, earthquakes, volcanoes

example- Japan- eurasian + N american + pacific + Philippians plates are under japan - pac +phil plates formed ocean trench (mariana trench)

destructive- subduction - description

-oceanic + continental plates move towards each other

-denser oceanic plate is subducted under continental plate into earths mantle- oceanic plate is recycled

conservative- plate margin- direction of movement,tectonic features and example

direction of movement- 2 plates move parallel to each other, either opposite direction or same direction dif speeds

tectonic features- earthquakes-can be mega if they get stuck for longer

example- San Andreas fault stretches 800km through California in USA- N american(6cm per yr) + pacific plate(10cm per yr)

conservative description

-pressure builds up at margain of tectonic plates- as they’re pulled along behind a plate

-as they move past friction makes them stuck

-pressure builds until the rock fractures in an earthquake

summaries ridge push/ gravitational sliding

-hot magma (that rises at a mid-ocean ridge) heats the rock arounf the magma

-asthenosphear and lithosphere geat and expand + elevate above sea floor- produces a slope down and away from the ridge

-rock forms from magma and gets older (more dense) gravity makes this lithosphere slide away from ridge and down the sloping asthenosphere

-magma makes new lithosphere

where can earthquakes happen

constructive and both destructive plate (collision and subduction) margins

why do earthquakes occur

friction causes 2 plates to get stuck and pressure builds up. then pressure is suddenly released so seismic waves radiate from the focus

what are seismic waves

waves of energy released during an earthquake

whats the focus

the point at which the earthquake occurs under the Earths surface

whats the epicenter

the point on the Earths surface directly above the focus

whats the magnitude

the measure of the amount of energy released during an earthquake

whats the magnitude measured using

Richter scale

whats the Richter scale

a logarithmic scale where each number is 10x bigger than the one before

what type of plate boundary do volcanoes occur

constructive and only subductive destructive plate boundaries

when do volcanoes form

when magma rises through cracks/weaknesses in earths crust. pressure builds and magma explodes to the surface causing a volcano eruption

and the lava cools to form new crust

whats the magma chamber

collection of magma below the volcano

where does the magma excape from

main and secondary event

what are volcanoes that erupt regulaly called

what are volcanoes temperaly inactive called

what are volcanoes that aren’t likely to erupt again called

active

dormant

extinct

what are volcanic eruptions measured using

the volcanic explosivity index (VEI)

tectonic hazard

natural hazard caused by movement of tectonic plates (including volcanoes and earthquakes)

atmospheric hazard

hazards originating on Earths surface

geomorphological hazard

hazards originating on Earths surface

biological hazard

hazards caused by living organisms e.g dieseies and animals

hazard risk

probability/chance that a natural hazard may take place

asthenosphere

upper layer of earths mantle

lithosphere

more rigid outer part of earths crust

oceanic crust

thinner part of earths crust

contiental crust

thicker part of earths crust

tectonic plate

a rigid segment of the earths crust which ‘float‘ across heavier, semi molten rock below

plate margin

margin/boundary between 2 tectonic plates

convection

the transfer of heat energy in liquids and gases

slab pull

when the weight of a dense tectonic plate is subducted into the mantle

earthquake

sudden/violent movement within the Earths crust followed by a series of shocks

volcano

an opening in the earths crust from which lava,ash and gases erupt

hot spot

where the earths crust is particularly thin, magma risus up through the crust becauses of a static source of magma away from plate margins

primary effect

the initial impact on people and poverty, caused by the ground shaking e.g businesses being destroyed

secondary effects

the after effects that occur as indirect impacts, sometimes on a larger timescale e.g unemployment

seismic waves

shock waves released by the rupture of rock during an erathquake

focus

the point inside the eraths crust where the earthquake originates from

epicentyre

the point on the earths surface directly above the focus

magnitude

a measure of earthquakes size and remains unchanged with distance from the earthquake

richter scale

a logarithmic scale used for meaasuring the magnitude (strength) of an earthquake

active volcano

dormant volcano

extinct volcano

volcano that erupts regularly/shows signs of eruption

temperalily inactive volcano

never likely to erupt again

magma chamber

a collection of magma below the volcano

immediate response

the reactions of people as a disaster happens and in the immediate after math

long term responses

later reactions that occur in the weeks, months and years after an event

seismometer

internal part of the seismograph

latitude

a line drawn down from weast to east on a map, showing where places lie relative to the equator and poles

insolation

the amount of solar radiation (sun light) an area receives over a specified amount of time

where is L’aquila, Italy

whats the region

surrounding regions

river

is in the region of Abruzzo and is in Europe in the East of Italy and its surrounding regions are Teramo, Pescara, Cheitai and Molise in the east and south and in the west rome is surrounding. There is a river running through L’aquila from the North to centre and runs east to the ocean

L’aquila italy (2009)

primary effects (4)

buildings collapsed (churches, medieval buildings+monuments with cultural value

national mueseum collapsed

hospital severly damaged and patiens evacuated

several buildings in the uni and some facilities in student accommodation collapsed

L’aquila italy (2009) - HIC

secondary effects (5)

• aftershocks - triggered landslides, rockfalls causing housing and transport to be damaged

• landslide + mud flow was caused by a burst main water supply pipeline near Pagaino town

• number of students at L’Aquila Uni w=decreased

• lack of housing/rent - hosuing prices inc

• much of cities central businesses was corded off due to unsafe buildings - some ‘red’ zones still excist which has reduced the amount of business, tourism + income

immediate responces of the earthqauke - L’aquila (3)

• homeless hotels provided shelter for 10,000 - 40,000 tents given out

• within the hour Italian red cross searxhed for survivors, helped by 7 dog units, 36 ambulances + tempary hotel, water, hot meals, tents, blankets given put - british 5red cross raised £171,000 in support

• mortages + bills for sky tv, gas and electric were suspended, italian post office offered free mobile calls, raised donations and gave free delivery for small businesses

long term responces to l’aquila (4)

• torch lit procession with catholic mass on anniversary of earthquake as a rememberance

• residents didnt pay taxes in 2010

• students given free public transport, dixcounts on educationalachievement and no uni feesfor 3 yrs

• homes took av 15 yrs to rebuild + historic centres

L’aquila earthquake

when

richter sclae

apicenter

killed

injured

homeless

colapsed

April 6 2009 at3:32 am

6.3 richtor scale

epicenter - 7km

308 killed

1500 injured

67500 homeless

aprox 10-15,000 buildings colapsed

Gorka Earthquakr (2015) - LIC

when

magnitude

aprile 25 2015

7.8

where is Gorka Earthquakr (2015)

Nepal in north of Barpak- near himalays

surrounding countries is china + India

Nepal is landlocked

Primary effects Gorka Earthquakr (2015)

• 8,841 died, 16800 injured + 1 mil homeless

• historic buildings + temples in Kathmandu (e.g Dharahara tower) - 200 ppl where trapped, many buildings collapsed as no compulsary bui;lding standards

• 26 hospitals and 50% schools destroyed

• reduced supply of water, food and electricity

• 352 aftershocks + second earthquake on 12 may 2015 measuring 7.3 magnitude

secondary effects of Gorka Earthquakr (2015)

• earthquake triggered avalanche on mount Everest - 19 died

• 2014 - world travel + tourism council reported tourism was down 8.9% of Nepals GPD - will inc when nepal recovceres

• food + income lossed - rice thats planted was ruined from earthquake - 2/3 of population depend on farming, rice seeds stored in homes lost too

immediate responses of Gorka Earthquakr (2015)

• nepal requested interational help but the UKs disasters ermergancy committee (DEC) raised US $ 126 mil by september 2015 providing emergancy aid and rebuild worst-hit-areas

• temperary shetters set up - red cross gave 225,000 people tents

• UN health agency + world health organisation (WHO) distributed medical supplies to worst-affected districs- important as monsoon season arrived early, inc risk of waterbourn diseases

• nepals mountainous terrain makes it difficult for aid for these remote villages - 315,000 people cut off by road and 75,000 unreachable by air - facebook launched safety feature so people could say their safe - companies didnt charge phone calls

long term responses of Gorka Earthquakr (2015)

• Nepals government (+UN,EU,Wolrd bank,Japan,internatinal agency, Asain development) carried out Post-disaster neeeds assessment - reported 23 areas needed rebuilding. 8 months after earthquake office for the coordination of humiliation affairs (OCHA) reportedUS$ 274 mil of aid had been commited to recovery efforts

• Durbar square heritages reopened in june 2015 - to encourage tourists back - mount everest reopende for touresrs aftersome stretches of trail moved

• recovery phase started 6 months later by the food and agriculture organization of UN - to expand crop production individuals trained how to maintain and repair irrigation channels damaged by landslides in earthquake

2 statists about ppl living near volcanoes

8% of world pop live near volcanoes

50% of 320 million ppl in usa are at risk of earthquakes

why do ppl live near earthquakes

mostly to do with money

• geothermal energy

• farming

• mining

• tourism

• family friends, feeling

pros,cons of geothermal energy (3,1)

0 carbon energy

renweable

reduces green house gases + effects of climate change

cons

cant do this everywhere

how does geothermal energy work

steam (heated by magma) then boreholes are drilled into the rock to harness the hot steam - which turns turbines at power stations

geothermal energy provides 30% of icelands total electricity

why do people live by volcanoes - farming

• lava + ash from volcanoes kill livestock + destroy crops

• after 1000s yrs weathering of this lava releases minerals and leaves beg=hind very fertile soil

• land can be farmed productively and produces food + income

volcanic soild on >1% of earths surface but support 10% world population.

why do people live by volcanoes - mining (2)

why is mining in active volcanoes dangerous (3)

why do miners still work despite this (1)

• settlements develop where valuable minerals are found - as jobs are created here

• Kawah Ijen is an active volcano in East Java - crater has loads of sulphur (can be made inti medicine)

• miners cant afford protective clothing

• hydrogen sulphide + sulphur dioxide gases burn their eyes + throat - respitory diseases

• in the last 40 yrs 74 miners have died becasue of the fumes

• miners earn $6 a day (more than coffee plantations) so is worth it

why do people live by volcanoes - Tourism