Chapter 0 - Natural Hazards Flashcards
Name as many natural hazards you can
Floods, droughts, typhoons/hurricanes/tornados/ cyclones (tropical), sand/thunder and lightening storms, monsoon rain, heavy snow fall, heat wave, blizzard, earthquake, volcanoes, avalanche, meteorite, landslides, etc
Name our 2 Earthquake case studies, where they were and the main differences.
Christchurch, New Zealand, MEDC - More Economically Development country, February 2011, 22
Nepal, LEDC - Less Economically Developed Country, April 2015
What is the main cause resulting in a increase in extreme weather events?
Global warming
What was out main storm case study? Where was it ? When?
Typhoon Haiyan, the Philippines, 2-11 November 2013
What is the hazard risk of an area?
The probability or chance a natural hazard may take place
What are the main natural hazards that occur in the UK?
Landslide, heat wave, drought, electric storm, heavy snow, blizzards, rarely earthquakes, rarely wild/forest fires
How can the season effect natural hazards?
Some natural hazards depend on the season, which can mean in places with noticeable seasonal variation, like the UK, they only occur in part of the year
How can location effect natural hazards?
Some hazards, like earthquakes or tropical storms, only occur in certain areas, whereas other areas are less likely to be effected
How can the development of an areas effect the impact of natural hazards?
How likely it is to be impacted, because if the place is less developed it may have a lack of protection, education, warning systems, etc
Less developed areas are often more poorly constructed than more developed areas (in a tsunami those in a concrete building more likely to survive than those in a hut)
Name some key factors that will be part of how bad the impacts of natural hazards are
The time it takes place, the frequency (are they prepared? Happens often?), the magnitude (size), level of development/ wealth, natural factors (flat or hilly land), population density and distribution, location, education of people (do they know what to do to prevent damage?)
How does population density and distribution effect the severity of a natural hazard?
The number of people living in an area will effect how many people are injured, an earthquake in the middle of the country side will have less of an impact than if it were to be in the middle of London
State the 4 main layers of the Earth and their temperatures working your way out from the centre
The inner core 7000 degrees Celsius , the outer core 4000, the mantle 1000, the crust (ranges -50 to 50 approx)
What are the 2 layers of the crust (this is extra knowledge don’t worry too much about it)?
The lithosphere then bellow nearer the mantle the asthenosphere
What drives convection?
Radioactive decay in the inner core
What key process occurs in the mantle? What does this do and how does it work?
Convection occurs in the mantle because it is molten and can move so hot molten rock is pushed up to the crust then as it cools it is pushed away, sometimes moving plate boundaries on the crust with it then as it cools more it sinks back down to be heated again
What are the 2 types of crust? Name their key characteristics
Oceanic and continental crust
Oceanic crust is very dense and is made of basalt salt but is quite young (200 million years) as it can be destroyed and is renewable and is 5-10km in depth
Continental crust is not very dense and is made of granite and is very old (1500 Million - 3.8 billion years) as it is not renewable and cannot be destroyed and is 30-50km in depth
How do we know all continental plates are quite old on Earth?
As they are still the same shape and would fit together in an old supercontinent called Pangea
Describe where Earthquakes and volcanoes are located?
Most of them are located along tectonic plate boundaries and are rather clustered or sparsely spaced, volcanoes are mainly coastal. Lots of earthquakes in the Philippines lots of volcanoes in Iceland
What are the types of tectonic plate boundaries? Which ones the odd one out?
Destructive, constructive, conservative, collision and uncertain
Uncertain is the odd one out as it is not just one type and one impact like the others
Give an example of a destructive boundary
The Philippines and Pacific plates
Give an example of a constructive boundary
Pacific plate and Nazca plate
Give an example of a conservative boundary
Antarctic and Nazca plate
Give an example of a collision boundary
Eurasian and African Plates
Give an example of an uncertain plate boundary
The middle of the African plate
What is a natural hazard?
A natural process which could cause death, injury or disruption to humans or damage of properties and possessions
What is a natural disaster ?
A natural hazard that has actually happened
What are the 2 main types of natural hazard?
Geological hazards and meteorological hazards
What are geological hazards?
Hazards caused by land or tectonic processes, such as volcanoes, earthquakes, landslides, avalanches
What are meteorological hazards?
Hazards caused by weather or climate, such as tropical storms, heat waves, climate change
What happens at a conservative plate margin?
2 plates are moving sideways past each other or in the same direction at different speeds, this means no crust is lost. However if they get stuck then suddenly carry on moving it can cause an earthquake
What happens at destructive plate margins?
2 plates are moving towards each other, one oceanic crust the other continental or (in collision when 2 continental plates meet and force land upwards). The denser oceanic plate is forced bellow the continental one into the mantle and destroyed, this forms ocean trenches (where the plate goes down) and volcanoes and earthquakes
What are constructive margins?
2 plates are moving away from each other and magma rises from the mantle to fill the gap, and cools, creating a new crust and volcanoes and earthquakes
At which type of plate margins do earthquakes occur?
All of them
Conservative : as they get stuck
Constructive : as they move away from each other tension builds in cracks in the plate
Destructive : as they get stuck
What happens to cause an earthquake?
Tension occurs at a plate boundary, the plates eventually jerk away from each other causing a shock wave (the earthquake), the shock waves spread out from the focus in the Earth (being nearer this causes more damage), the earthquake can then be measured using the Richter scale or moment magnitude scale
What is the epicentre?
The point on the surface of the Earth directly above the focus of the Earthquake, where there is often most damage
What do I mean when I say that the Richter scale is logarithmic? Hint: think how the scale increases
Every time the scale increases by 1 it increases by times 10
E.g. a magnitude 7 earthquake is 10 times more powerful than a magnitude 6 earthquake
What are primary effects of natural hazards? Give examples of that of an earthquake
The immediate impacts, such as of the ground shaking, places destroyed, places damaged (like electricity cables, pipes, roads, etc)
What are secondary effects of natural hazards? Give some examples of that of an earthquake
The impacts that happen later on, often as a result of the primary effects. Such as in an earthquake the primary effects can trigger landslides and tsunamis, which cause more injury and death, leaking gas can be lighted, people left homeless, shortage of food and water, access for aid and trade can be hard, businesses destroyed, lack of jobs, repairs and reconstruction can be very expensive
Which has more effects primary or secondary effects?
Secondary, there are a lot of knock on impacts
Give some key pints of evidence which supports plate tectonics
Pangea super continent, fossils placement, concentration of volcanoes and earthquakes, the mantle in general
At what plate boundary did the Christchurch earthquake occur? What type of margin was it?
Between the Australian plate and Pacific plate, this is a destructive plate margin
What was the magnitude of the Christchurch earthquake? Using the Richter scale
6.3
How many people died and were injured and made homeless in the Christchurch earthquake?
185 died
2, 500 approximately injured
1000s made homeless
What were the responses to the earthquake in Christchurch like?
$900 million paid in building claims
Grants for children who’s school had been interrupted
Aid offered from Australia and other countries
Tempora houses provided
What was the magnitude of the Nepal earthquake using the Richter scale?
7.9
Out of Christchurch and Nepal which had:
The bigger earthquake magnitude
Most deaths
Most/ severe impacts
Nepal was bigger, more deaths occurred and the impacts were worse as it didn’t have enough money to support itself easily
How many deaths and injuries and people being made homeless occurred in the earthquake in Nepal?
8,000 deaths, 14,500 injured and over 2.8 million made homeless
Compare how much money it took to rebuild Nepal and Christchurch, consider Nepal is a country Christchurch a city
$900 million Christchurch
$200 million Nepal, much less, less valuable property
What does the Richter scale measure?
How powerful an earthquake is, easily comparable. This is done by using a seismometer as it shows the energy the earthquake uses
How is the Richter scale measured?
It goes up by 10 x each number, so 9 is 10,000 times greater than that of 5
What is the Mercalli scale? How is it measured?
It measures the effects of the movement of an earthquake, it is based on opinions and isn’t always accurate and isn’t comparable to the Richter scale
What is the range the Mercalli scale is measured? What about the Richter scale?
1-12 Mercalli
1-10 Richter
What’s a temblor?
An American word for an earthquake
What is a tremor?
A slight earthquake/ quivering movement of the Earth
What is adaptation?
Changing something in order to help deal with/ decrease the impacts
What is mitigation?
Changes in order to decrease the causes of a problem
How does air move around the earths atmosphere?
Warm air rises at the equator (to one of the poles) then sinks back done to the equator as it is cooler
What is air pressure? When does low and high air pressure occur?
When the air moves it causes different pressures. High pressure occurs when air is sinking whereas low pressure occurs when air is rising. Wind moves Fremont high to low pressure
There are 6 separate, 3 different types of ‘belts’ or cells around the Earth which air circulates through the entire depth of the troposphere. What are these 3 (2 of each) cells and where are they located?
The Polar cell, both poles
The Hadley cell, either side of the equator
The Ferrell cell, in between the Hadley and Polar cells
What is the Gulf Stream?
A powerful warm current which operates in the Atlantic. It is driven by wind surface patterns. It circulates it’s warmth then cools and sinks deeper then circulates it’s way back through a Deep South current.
Why is the Gulf Stream key to the UK?
It brings warmth to the UK as it passes just West of the UK so it has a large impact, which makes the UK have milder winters
What would happen without the Gulf Stream? If it stoped due to global warming?
Some scientists say it would make Europe’s temperature plunge dramatically, others say it would make nice weather by balancing out global warming
Compared to the equator where about do the 3 tropical storms occur? (They are all the same storm just in different parts of the world)
Cyclones, Southern Hemisphere where Australia is located
Typhoons, northern hemisphere where the Philippines/ South Asia is located
Hurricanes, northern hemisphere where Mexico and America are located
They all only occur in tropical areas
What direction do tropical storms travel?
Away from the equator
Give the rough sequence for what happens/ how a tropical storm forms
Strong upward movement of air draws water vapour up from warm surface, this evaporated air cools as it rises and condenses to form thunderstorm clouds, the condensing air releases energy which powers the storm and draws up more water. Several small storms can join to form a giant one, when surface winds exceed 120km/h a tropical storm has officially been born . The storm then develops an eye where the air rapidly descends. The storm is carried across the warm water as it gathers strength and energy until it reaches land and its energy is cut off and weakened by the friction of the band but causes damage with its energy to anything in its way.
How fast does a tropical storm have to have surface winds of until it officially becomes a tropical storm?
Wind speeds of exceeding 120km/h
Where is the most intense and strongest winds located in a tropical storm?
In the eye wall on the edge of the eye
What does there have to be (the one key thing) for a tropical storm to form?
It must be located over warm waters
How are tropical storms measured? What scale is used?
The Safari Simpson scale, measured 1-5 (5 being the worst) depending on, wind speeds, storm surge (possibly predicted using wind speeds)m the central pressure and therefore with all of these the overall damage
What are the main parts of a tropical storm? Which way does it rotate?
A tropical storm is made up of the eye (cold falling air), the eye wall ( warm rising air), rain bands (warm rising air and cold sinking air) and the outflow cirrus shield ( strong winds around main part of storm)
How large can tropical storms become?
Up to 480km across
What’s found in the eye wall?
Torrential rain, thunder/lightening and extremely strong winds over 200km/h
What happened to the Philippines when typhoon Haiyan hit?
Severe impacts on all 7,000 islands that make up the Philippines, 6,000 dead, around 2,000 injured and 4 million homeless, houses uprooted, large storm surge flooded large amounts of land with 20 feet of water which washed everything away
