Techtonic And Natural Hazards Flashcards
What’s the definition of a hazard
The event that has the potential to threaten life and property
What’s a natural hazard
Something we cannot control
What’s a human hazard
A hazard caused by humans
What’s an atmospheric hazard
Weather hazards such as hurricanes
What’s a geomorphological hazard
Hazards that occur on the earths suface
What’s a biological hazard
A hazard that involves living organisms such as forest fires
What’s a choropleth
A map that uses colour to show data
What are the most extreme places
High population, equator and ring of fire
Why is the magnitude and frequency of natural hazards increasing
Human influences, global warming, deforestation and urbanisation
What’s a plate boundary
Where two plates meet
What will you find distributed on plate boundarys
Volcanoes and earthquakes
How can plates move
Towards, away and side to side from each other
What does a constructive boundaries do
Makes land and has volcanoes
What does a conservative plate boundary do
Protects land and has earthquakes
What does a destructive-subduction plate boundary have
Earthquakes and volcanoes, also has a risk of Tsunamis
What does a destructive-collision plate boundary have
Mountains and earthquakes
What type of plates are on a constructive Plate boundary
Oceanic
Which way are the oceanic plates moving on the constructive Plate boundary
Opposite directions
What creates land
Underwater volcano
What are the different types of volcanoes
Shield and composite
At the Destructive-S Plate boundary, what are the different plates
Oceanic and continental
Which way do the destructive-S plate boundaries move
Towards each other
What are the types of plates at the conservative Plate boundary
Both continental
What is built up at a conservative Plate boundary
Potential elastic energy
What are the conservative Plate boundaries
Dangerous but easy to predict
What happens at a collision Plate boundary
Two continental plate boundaries are moving towards each other
What does the collision Plate boundary produce
Foal mountains and earthquakes
Where is Montserrat
Caribbean island, subductive soufriere hills
Who evacuated the island
Half of the population
Where is the exclusion zone on Montserrat
South
What were the primary effects
2/3 of the island covered in ash, forest fires caused by pyroclastic flow
What were the secondary effects
Harsh living conditions, port and airport closed
What are the types of volcano management
Monitoring, prediction, protection and planning
Name some monitoring techniques
Seismicity, hydrology( lake nyos ) geophysical measurement
How can you plan for an eruption
Create exclusion zone, evacuation plan, food, funds
Where does air rise
At the equator
What effect does this have on the equator
Low pressure and rainfall
Where does air fall
The poles as it’s cold
What effect does this have on the poles
High pressure and dry conditions
Where are these conditions located compared to the equator
30° north and south
Where does air rise again compared to the equator
60° north and south
Finally where does it descend again compared to the equator
90° north and south
Explain the location of the cells
Hadley cell at 30°
Ferrel cell at 60°
Polar cell at 90°
Describe a tropical storm
A very powerful, low pressure weather system which results in stormy winds and heavy rainfall
Name three other names for tropical storms
Cyclones, hurricanes and typhoons
What causes a tropical storm to spin
The Coriolis force caused by the rotation of the earth
Which way does the air flow inside the eye
It descends
What surrounds the eye and what causes this
Cumulonimbus clouds surround the eye and they are caused by warm moist air condensing as it rises
How do tropical storms develop
Between 5° and 30° latitude
Initially move westward due to easterly winds
27°c minimum water temp
Quick draw of air causes strong winds
Why do tropical storms lose energy when they reach land
Because they are no longer receiving heat energy and moisture from the ocean which is needed to drive the storm
Why can global warming cause more places to get tropical storms
Because the oceans are getting heated nearer to 27°c
What is the focus of an earthquake
The point inside the earths crust where the earthquake originates
Where are the seismic waves the most powerful
At the epicentre
What is the epicentre
The point on the earths surface directly above the focus
How are earthquakes measured
On the Richter scale using seismometers
What does the effect of an earthquake depend upon
It’s size Level of development Depth of focus/distance from epicentre Population density Time of day
What is the magma chamber
Where molten rock is stored beneath the ground
What is the main vent
The channel in which magma travels through to rea h the earths surface
What is the secondary vent
Where magma escapes through the side of the volcano if the main vent becomes blocked
What do volcanoes produce
Ash, lava, volcanic bombs, pyroclastic flows and lahars
Name three positive effects of volcanoes
Geothermal energy can be used where magma lies close to the surface
Ash is good soil fertiliser
Volcanoes attract tourists
Name three negative effects of volcanoes
Dangerous and can kill people and property
Disrupts economic activity as businesses find it hard to operate after eruption
Habitats are damaged by lava flows
Where are composite volcanoes found
At destructive plate boundaries
Name 4 characteristics of composite volcanoes
Acidic viscous lava
Steep sides with alternate layers of ash and lava
Violent eruptions
Longer periods of rest between eruptions
Where are shield volcanoes found
Constructive plate margins
Name 5 characteristics of shield volcanoes
Basic lava, runny Gentle sides as lava doesn’t solidify quickly No layers, just lava Less violent eruptions Shorter periods between eruptions
What is used to monitor volcanoes
Seismometers, tiltmeters, previous eruptions and measuring temperature
What do tiltmeters do
Monitor changes in landscape as volcanoes tend to swell before they erupt
Why do people live near volcanoes
Fertile ground for a higher crop yield
Tourism is high so it increases local economy
Geothermal energy for cheaper electricity
Minerals such as diamonds can be mined to make money
