Natural World - Physical

Question 1

What is a natural hazard?

Answer 1

A natural process which could cause death, injury or disruption to humane, or destroy property or possessions

Question 2

What are the different types of hazards?

Answer 2

1) . Geological hazards - caused by land and tectonic plates eg tectonic hazards earthquakes and tsunamis
2) . Atmospheric hazards - hurricanes, tornadoes
3) . Geomorphological hazards - flooding occurs on earths surface
4) . Biological hazards - a forest fire which invloves living organisms
5) . Meteorological hazards- tropical storms they’re caused by weather and climate

Question 3

What is a hazard risk?

Answer 3

A chance or probability of being affected

Question 4

How does urbanisation affect the risk from natural hazards?

Answer 4

Over 50% of the worlds population now live in cities, densley populated urban areas are at great risk from natural events eg earthquakes and tropical cyclones

Question 5

How does climate change affect the risk from natural hazards?

Answer 5

In a warmer world, the atmosphere will have more energy leading to more intense storm and hurricanes.
Climate change may cause some parts of the world to become wetter with an increased risk of flooding.
Other areas may become drier and become prone to droughts and famine

Question 6

How does poverty affect the risk from natural hazards?

Answer 6

In poorer parts of the world, poverty may force people to live in areas at risk, this is true in cities like Lima in Peru where a shortage of houses has led go people building on unstable slopes prone to floods and landslides

Question 7

How does farming affect the risk from natural hazards?

Answer 7

When a river floods it deposits fertile silt on its floodplain, but when people choose to live there they’re putting themselves at risk.
In low lying countries people may live on floodplains

Question 8

What happens at the constructive plate margin?

Answer 8

Two plates are moving apart

• eg at the mid Atlantic ridge, magma is forcing its way to the surface, as it breaks through the overlying crust it causes earthquakes
• on reaching the surface it forms volcanoes, the magma here is very hot and fluid, lava erupting from a volcanoe will flow a long way before cooling which forms broad and flat shield volcanoes

Question 9

What happens at a destructive plate margin?

Answer 9

Two plates are moving towards each other

• where two plates meet a ocean trench has formed, the oceanic nazca plate which is dense, is subducted beneath the less dense south american plate
• friction between the two plates causes earthquakes
• as the oceanic plate moves down it melts, creating magma which breaks through to the surface to form steep sided composite volcanoes

Question 10

What doesnt happen when two continental plates meet?

Answer 10

Theres no subduction, when two plates collide and the crust becomes crumpled and uplifted it forms fold mountains eg himalayas

Question 11

What happens at a conservative plate margin?

Answer 11

Two plates are moving past each other

• friction betwen the plates causes earthquakes, a well known example is the San Andrea Fault in california.
• > the faster moving Pacific plate is sliding in the same direction next to the slower moving north american plate
• earthquakes happen along conservative margins as stress gradually builds up over many years; they can be destructive as they’re close to the earths surface

Question 12

Why do people live in hazardous areas?

Answer 12

• farming is quite good in volcanic areas as ash makes soil fertile
• they actually cant move due to cost, lack of knowledge and language
• people dont want to go as they feel optimistic it wont happen as they dont happen very often
• its worth staying as they have family and friends there
• better building design can withstand earthquakes so people feel less at risk

Question 13

When and where did Chile’s earthquake happen?

Answer 13

Took place on the 27th February 2010, with a measurement of 8.8 on the richter scale
- it occurred off the coast at the destruction plate margin where the nazca plate subducted the south american plate

Question 14

What are the primary effects of chiles earthquake?

Answer 14

1) . Around 500 people killed and 12,000 people injured, 800,000 people affected
2) . 220,000 homes, 4500 schools, 53 ports, 56 hospitals and other public buildings destroyed
3) . Cost if earthquake estimated at US$30 billion

Question 15

What are the secondary effects of chiles earthquake?

Answer 15

1) . 1500km of roads damaged, mainly by landslides- remote communities cut off for many days
2) . Several coastal towns devastated by tsunami waves
3) . Fire at chemical plant near santiago meant area had to be evacuated

Question 16

What are the immediate responses to chiles earthquake?

Answer 16

1) . A national appeal raised 60 million dollars, enough to build 30,000 emergency shelters
2. Emergency services acted swiftly. YInternational help needed to supply field hospitals, satellite phones and floating bridges
3) . Temporary repairs made to route 5 north-south highway within 24 hours enabling aid to be transported to affected areas

Question 17

What are the long term responses to chiles earthquake?

Answer 17

1) . A month after the quake Chiles government launched a housing reconstruction plan to help nearly 20,000 households affected
2) . Chiles economy, based on copper exports could be rebuilt without the need for much foreign aid
3) . The president announced it could take 4 years for chile to fully recover

Question 18

When and where did Nepal’s earthquake take place?

Answer 18

Took place on the 25th April 2025, it measured 7.9 on the richter scale
- the epicentre was 80km to the NW of Nepal’s capital, where the destructive plate margin is; the indo-australian plate is colliding with the eurasion plate. The earthquake was very shallow

Question 19

What are the primary effects of Nepals earthquake?

Answer 19

1) . 9,000 people died and 20,000 injured, over 8 million people affected
2) . 3 million people left homeless
3) . 1.4 million people needed food, water and shelter in the days and weeks after the quake

Question 20

What are the secondary effcts of nepals earthquake?

Answer 20

1) . Ground shaking triggered landslides & avalanches, blocking roads and hampering relief efforts
2) . An avalanche in langtang region left 250 people missing
3) . Avalanches in mount everest killed at least 19 people, greatest loss of life on the mountain

Question 21

What are the immediate responses to Nepals earthquake?

Answer 21

1) . Search and rescue teams, water & medical support arrived quickly from countries such as Uk, india and china
2) . Half a million tents needed to provides shleter for homeless
3) . Helicopters rescued many people caught in avalanches and delivered supplies to villages cut off by landslides

Question 22

What are the long term responses to nepals earthquake?

Answer 22

1) . Thousands of homeless people to be re-housed, and damaged homes repaired, over 7000 schools to be rebuilt or repaired
2) . Stricter controls on building codes
3) . Tourism, a major source of income to be boosted, in july 2015 heritage sites were reopened

Question 23

What is monitoring?

Answer 23

Using scientific equipment to detect warning signs of events such as a volcanic eruption

Question 24

How does do monitoring in volcanoes work?

Answer 24

As magma rises through a volcano it gives a number of warning signs

• moderns high tech equipment some which are located on the volcanoe, allows scientists to monitor activity
  1) . Remote sensing - satellites detect heat & changes to volcano shape
  2) . Geophysical measurements- detect changes in gravity as magma rises to surface
  3) . Gas - instruments detect gases released as magma rises

Question 25

How does monitoring in earthquakes work?

Answer 25

Earthquakes generally occur without warning, whilst theres some evidence of changes in water pressure, ground deformation & minor tremors prior, scientists are yet to discover reliable ways to monitor & predict quakes

Question 26

What is prediction?

Answer 26

Using historical evidence & monitoring, predictions can be made about when and where a hazard may happen

Question 27

How do predictions in volcanoes work?

Answer 27

Predictions of a volcanic eruption is based on scientific monitoring eg in 2010 the increase in volcanic activity in Iceland enabled scientists to make accurate predictions

Question 28

How do predictions in earthquakes work?

Answer 28

Its impossible to make accurate predictions about earthquakes due to lack of warning signs however historical records have allowed scientists to identify locations that they believe are at greatest risk

Question 29

What is protection?

Answer 29

Designing building that will withstand tectonic hazards

Question 30

How does protection work in volcanoes?

Answer 30

Sheer power of volcanic eruption means that there’s little that can be done to protect people and property
- but using earth embankments or explosives to divert lava flow away from property can be done

Question 31

How does protection work in earthquakes?

Answer 31

Earthquake protection is the main way to reduce risk. Its possible construct buildings and bridges to resist the ground shaking associated with a quake.
Its possible to construct tsunami walls at the coast to protect people and nuclear power stations

Question 32

What is planning?

Answer 32

Identifying and avoiding places most at risk

Question 33

How does planning work in volcanoes?

Answer 33

Hazard maps are used to show the worlds most dangerous volcanoes, they can be used to restrict certain land uses or identify which areas need to be evacuated when a eruption is going to occur

Question 34

How does planning work in earthquakes?

Answer 34

Maps can be produced to show the effects of an earthquake or identify those areas at most risk from damage so high value land uses eg hospitals and reservoirs can be protected

Question 35

What is global atmospheric circulation?

Answer 35

Helps to explain the location of the world climate zones and the distribution of weather hazards

Question 36

Whats the most important influence on worldwide variations in climate?

Answer 36

Latitude - because of the curved surface of the earth the equator recieves much higher insolation than the polar latitudes.
- parallel rays of the sun are spread thinly when they strike the earths surface at high latitudes, whereas low latitudes sunlight is more concentrated.

Question 37

What happens as a result of the suns ray?

Answer 37

The air at the equator is heated strongly, becomes less dense and rises to a high altitude. This creates a global climate zone of low pressure, the equatorial zone
- after rising air spreads out and flows towards the north and south poles

Question 38

What does low insolation at polar latitudes do?

Answer 38

Results in colder, denser air and high pressure. As air sinks towards ground level, it spreads out and flows towards the equator.

Question 39

What provides a simple basis for a convection cell?

Answer 39

Low pressure belt at the equator and the high pressure belt at the poles

Question 40

Where else are there high pressure belts?

Answer 40

Tropics of cancer and capricorn, air sinks towards the ground, as it descends the air warms and results in high pressure and hot dry desert conditions.
- This circulation of air between the tropics and the equator is the hadley cell

Question 41

How many cells does global circulation depend on?

Answer 41

Three, as the earth rotates on its axis, the movement generates strong, high altitude winds which wrap around the planet like belts.
- These winds flow towards the east as the earth spins and interact with convection cells

Question 42

What are jet streams?

Answer 42

Two particularly strong, high altitude currents of air

Question 43

Why are surface winds important?

Answer 43

For transferring heat & moisture form one place to another

Question 44

Why do the exact positions of the jet streams and convection cells vary seasonally?

Answer 44

The tilt and rotation of the earth causes relative changes in the position of the overhead sun. These seasonal changes causes pressure belts & winds to move north during our summer and then south in our winter

Question 45

What is responsible for tropical storms?

Answer 45

The trade winds in the tropics drive tropical storms

Question 46

What is a tropical storm?

Answer 46

A huge storm that develops in the tropics, its a spinning mass of clouds

Question 47

What else are tropical storms called?

Answer 47

In the usa & Caribbean- hurricanes
In the philippines & japan - typhoons
In SE asia & Australia - cyclones

Question 48

Where do tropical storms form?

Answer 48

Over warm oceans; mostly north and south of the equator as theres not enough spin from the rotation of the earth.

Question 49

What is the corolis effect

Answer 49

Wind blows from areas of high pressure to areas lf low pressure as the earth rotates it causes the wind to bend

• this is because the earth has a curvature with the equator far wider than the plates, therefore the earth has to spin faster at the equator.
• this difference in speed means the wind bends as it blows across the earth -> corolis effect

Question 50

How do tropical storms form?

Answer 50

1) . A strong upward movement of air draws up water vapour from the warm ocean surface
2) . The evaporated air cools as it rises & condenses to form thunderstorm clouds
3) . As air condenses, it releases heat which powers the storm & draws more water from the ocean
4) . Several smaller thunderstorms join to form a giant spinning storm, when surface winds reach an average of 120km per hour it becomes a tropical storm
5) . Storm now develops an eye at its centre where air descends rapidly. The outer edge is the eyewall where most intense weather conditions are felt
6) . As storm is carried across the ocean by prevailing winds it gathers more strength
7) . On reaching land, the storms energy supply (evaporated water) is cut off. Friction with land slows it down & begins to weaken. If the storm reaches warm seas after crossing the land, it may pick up strength again.

Question 51

Whats the structure of a tropical storm?

Answer 51

1) . Beyond the eye wall there are futher banks of clouds with thunderstorms & occasionally tornadoes, there will also be gusty winds and heavy rain
2) . The central eye can be seen, its a small area where cold air sinks towards the ground and warms up. There’s no clouds here & conditions are calm.
3) . On either side of the eye is the eye wall, which is a tall bank of cloud. Here, there are strong winds, in excess kf 120km/h, heavy rain, thunder & lightening

Question 52

How will the distribution of tropical storms be affected by climate change?

Answer 52

Sea temperatures in the tropics have increased by 0.25->0.5 degrees
- as patterns change, they may affect the distribution and in the future, tropicsl storms may affect areas outside the current hazard zone, such as the south atlantic and other parts of the Sub-tropics. Hurricanes may also becomes more powerful

Question 53

How will the frequency of tropical storms be affected by climate change?

Answer 53

Six of the ten most active years since 1950 have happened since the mid 1990’s.
- some computer models indicate that the frequency of tropical storms may decrease in the future but their intensity may increase

Question 54

How will the intensity of tropical storms be affected by climate change?

Answer 54

Hurricane intensity in the North Atlantic has risen in the last 20 years

• this appears to be linked to increase in sea surface temperatures
• but comparisons with past may not be completely reliable, more data will be needed over a longer period of time

Question 55

When and where did typhoon haiyan take place?

Answer 55

In november 2013, super typhoon haiyan hit the philippines, a category 5 on the Safir-simpson scale.
- huge areas of coastline and towns were left devastated with winds of upto 275km/h

Question 56

What are the primary effects of typhoon haiyan?

Answer 56

1) . About 6300 people killed - most drowned by storm surge
2) . Over 600,000 people displaced and 40,000 homes destroyed or flattened - 90% of tacloban city destroyed
3) . Over 400mm of rain caused widespread flooding

Question 57

What are the secondary effects of typhoon haiyan?

Answer 57

1) . 14 million people affected, many left homeless & 6 million lost their source of income
2) . Shortages of water, food and shelter affected many people, leading to outbreaks of disease
3) . Ferry services and airline flights disrupted for weeks, slowing down aid efforts

Question 58

What are the immediate responses to typhoon haiyan?

Answer 58

1) . Over 1200 evacuation centres were set up to help the homeless
2) . French, belgian and israeli field hospitals set up to help injured
3) . International government & aid agencies responded quickly with food, water and temporary shelters

Question 59

What are the long term responses of typhoon haiyan?

Answer 59

1) . Thousands of homes have been built away from areas at risk from flooding
2) . Aid agencies such as Oxfam supported the replacement of fishing boats a vital source of income
3) . The UN and countries including the US, Australia, japan, and the UK donated financial aid, supplies and medical support

Question 60

How does monitoring and predictions reduce the effects of tropical storms?

Answer 60

• developments in technology have made it possible to predict and monitor tropical storms more accurately and effectively.
  Eg in North Atlantic, there are two levels of warning issued by the national hurricane center in miami
  1). Hurricane watch - advises that hurricane conditions are possible
  2). Hurricane warning - advises that hurricane conditions are expected and that people should take immediate action

Question 61

How does protection reduce the effects of tropical storms?

Answer 61

There are a number of options available to protect people from the hazards

1) . Houses close to the coast constructed on stilts so that a storm surge will pass beneath
2) . Storm drains made in urban areas to take away any excessive amounts of rainfall and prevent flooding
3) . Sea walls built to protect key properties from storm surges

Question 62

How does planning reduce the effects of tropical storms?

Answer 62

Planning to reduce the tropical storm hazard is mainly done through raising awareness both to individuals and communities
Eg in the USA a national hurricane preparedness week takes place & focuses in educating about dangers and families are encouraged to devise their own plan of action should a warning be issued