natural hazards

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  • Created by: ZR1
  • Created on: 17-05-16 18:19

Predicting an earthquake


  • studying patterns of earthquakes
  • uses these patterns to predict the next one
  • seismograph shakes under the mass- records the relative motion


  • inert gas is released from rocks-granite
  • when they are fractured it goes at a faster rate


  • level of water in wells rises and falls-ground stressed before an earthquake
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Case study- Nepal

On Saturday 25th April 2015, an earthquake occured in Nepal. This was the worst natural disaster in Nepal in the last 80 years. The earthquake was a 7.8 magnitude. It happened on a collision boundary: Indo-Australien plate and the Eurasian plate.


  • 8617 people killed
  • 2.8 million people were homeless
  • 5.6 million people affected


  • government finds it hard to help the people
  • country is more poorer than before
  • 26 hospitals are damaged


  • entire villages are destroyed
  • water systems in hillside villages are wrecked
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Nepal earthquake responses

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Predicting for a volcanic eruption


  • used to detect small earthquakes/ movemen
  • when movement detected then there's pressure and energy-means that a volcanic eruption happen


  • detects lava flow movements/ where magma chamber
  • when magma rises to surface - there will be an eruption


  • used to check level of ground 
  • pressure causes- slight changes to shape/slope of volcano


  • collecting gas samples/ look at levels of the sulphur
  • more sulphur means more likely for an eruption to happen
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Preparing for a volcanic eruption

Warning System

  • people can prepare for evacuation
  • less people will die
  • less panic among the people

Evacuation plan prepared

  • easier for everyone 
  • no panic
  • no eruption- then people won't listen

Train emergency services

  • prevention of people dying
  • provides facilities for people affected

Organise emergency supplies

  • people have neccerities with them
  • no need of packing in rush
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How does the Earth's Crust look like?


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What are Earthquakes?

EARTHQUAKES-  is the result of the violent shaking of the ground caused by the movement of tectonic plates

FOCUS-  is the point in the crust where the actual earthquake occurs

EPICENTER- is the place at the surface of the Earth where the earthquake happens

SEISMIC WAVES- energy released from the earthquake

The Richter Scale measures the magnitude of an earthquake:

  • uses an instrument called seismometer
  • measured on a scale to 1-10
  • size 6 is 10 times more powerful than a size 5
  • it's 100 times more powerful than a size 4
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Case study- Christchurch

On Saturday 4th September 2010 there was an earthquake with a magnitude of 7.1. There were many aftershocks. It happened on a conservative boundary: Australian plate and Pacific plate.


  • around 2000 people were injured
  • water and sewage pipes were damaged
  • 50% Central City buildings severly damaged
  • 80% of city was without electricity


  • 181 people were killed in Aftershocks
  • business was out of action for a long time- losses of income and jobs
  • people affected mentally by the earthquakes needed support
  • Christchurch could no longer host Rugby World Cup matches - lost tourism, income 
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Earthquake diagram


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 A super volcano is a volcano on a massive scale

  • Super volcanoes are mostly in North-America and some in Asia
  • Mostly at destructive boundaries 
  • Some are at a hot spot e.g. north-American boundary


  • erupts at least 1000km cubed of material- regular volcano 1km cubed
  • erupts less frequently than regular volcanoes


  • magma chamber pushes upwards and the crust collapses-forms a caldera
  • magma trapped due to rock layer above
  • magma moves through a crack - mantle to the crust
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Volcanic Hazard- continue


  • hot/cold mixtures of water and rocks-flows down the slopes of the volcano
  • mixes with rainfall and snow
  • can trap people


  • hot molten rock erupted from volcano
  • damages property/destroy roads
  • it moves slowly
  • can out-run it

Volcanic gas

  • gas released from volcano
  • mainly carbon and sulphur-toxic
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Plate Boundaries

TECTONIC PLATES- are the surface of Earth cracked because of the movement in the mantle

PLATE BOUNDARY- where they meet

Constructive boundary

  • plates move apart
  • magma forces it's way through the gap created
  • new crust is formed at sea bed
  • underwater volcanoes are formed

Destructive boundary

  • plates move togethe
  • oceanic plate subducts under continental plate
  • ocean crust melted and destroyed- due to heat/pressure
  • explosive volcanoes/ violent earthquakes                                                                                
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Types of Volcanoes

  • Anactive volcanois a volcano that has had at least one eruption dduring the past 10,000 years.
  • Anextinct volcano is a volcano that hasn't erupted for at least 10,000 years, and isn't expected to erupt again.
  • Adormant volcanois an active volcano, which isn't erupting, but it's supposed to erupt again.
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Why do Volcanoes erupt?

In the Earth's mantle the pressure and the heat causes the rocks to melt and to form magma.

Magma pushes through the vents in the Earth's surface causing a volcanic eruption.

This can be due to plates moving towards each other or away

The magma comes to the surface. It's called lava now.

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Earth's Crust

HAZARD- is an extreme natural events which poses a life threat

CRUST- it’s made out of igneous/ sedimentary, and metamorphic rock. (Solid)

MANTLE- it’s made out of semi-molten rock. (Liquid)

OUTER CORE- it’s made out of iron and nickel. (Liquid)

INNER CORE- it’s made out of iron and nickel. (Solid)

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How does the Earth's Crust look like?


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Volcanic Hazard

Pyroclastic flows

  • happens when volcano erupts
  • parts of the volcano collapses
  • dangerous- can travel across water

Volcanic ash

  • made up of jagged rock, minerals, volcanic gases
  • destroys crops/stops economy
  • it's the product of eruption


  • when a side of the volcano collapses- caused by landslide
  • giant sea waves- caused by underwater earthquakes
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Plate Boundaries- types

Collison boundary

  • continental plates move together 
  • plates are too light to sink into the mantle
  • plates buckle and folds to form mountains
  • volcanic activity is rare/ violent earthquake

Conservative boundary

  • tectonic plates move in different directions/speeds
  • plates are locked by friction
  • pressure builds up until a plate breaks along a fault line
  • no volcanoes/violent earthquakes
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What are Volcanoes?

VOLCANOES- are the opening in the Earth's crust, where lava, ash, and the hot gases are ejected during the eruption

VENT-  the pipe up which the magma comes

SECONDARY CONE-  a small outlet through which magma erupts

ERUPTION-  a period of volcanic activity

VOLCANIC DUST-  solids from the volcano- smaller than 2mm

LAVA-  molten rock erupting from volcano


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What are Volcanoes?

VOLCANIC ASH-  solids form the volcano- larger than 2mm

MAGMA CHAMBER- the area beneath the volcano

VOLCANIC GAS-  fumes from the volcano

CONE-  the shape of the volcano

CRATER- the top of the volcano

MAGMA- molten rock before it erupted

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Earthquake Effects

PRIMARY- it's an immediate effect

SECONDARY- it happens after some time


  • people can be killed from an initial shaking of the ground
  • people are lest without food and water
  • lots of people can be injured
  • lots of homes can be destoyed-homeless people


  • strain on government to provide aid/help to people
  • tourist industry suffers- as people are less willing to visit a country
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Earthquake Effects- continue


  • damage to transport links/infrastructure e.g. roads
  • increase in level of crime
  • increase in the spread of disease- dirty conditions/water pipes affected
  • increase of fires-electrical eqquipment damaged
  • other hazards can result from an earthquake-landslides
  • frequent power cuts
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