Paper 1 - Natural hazards

Natural hazards

Natural hazards

Extreme natural events caused by natural processes that threaten or have the potential to cause damage, harm or destruction to property or human life

Would natural hazards still occur without humans?

Yes as they are caused by natural processes

Is a natural hazard still considered a natural hazard if it occurs nowhere near any humans or property?

No

Examples of natural hazards

• Earthquakes

• Volcanic eruptions

• Tropical storms

• Flooding

• Tsunami

• Droughts

• Tornadoes

• Wild/forestfires

Types of natural hazards

• Tectonic hazard

• Atmospheric hazard

• Biological hazard

• Geomorphological hazard

Example of tectonic hazards

Earthquakes and Volcanic eruptions

Example of atmospheric hazards

Tropical storm

Example of biological hazards

Forest/wildfires

Example of geomirphological hazards

Landslides/flooding

Natural disaster

When the damage or destruction actually takes place as a result of the natural hazard

Hazard risk

Probability or chance of a natural hazard occurring

Factors affecting hazard risk

• Population density

• Wealth

• Urbanisation/deforestation

• Geographical location

• Frequency

• Magnitude

• Global warming/climate change

4 layers of the earth

• Crust

• Mantle

• Outer core

• Inner core

Crust

The surface of the planet that we stand on on

What is the crust divided into?

• Oceanic crust - denser,heavier

• Continental crust - very thin

What is the thinnest layer of the earth?

Crust

What is the thickest layer of the earth?

Mantle

Which layers of the earth are solid?

Crust, Mantle and Inner core

What temperature can the inner core reach?

6000 degrees Celsius

Lithosphere

Crust and upper mantle

What is the lithosphere broken up into?

Several major fragments called tectonic plates - 7 major, 8 minor

Plate boundary

Where 2 plates meet along the edges

Name the 3 plate boundaries

Destructive, constructive and transform

Direction at transform margin

Side by side

Direction at constructive margin

Away

Direction at destructive margin

Towards

What landforms/hazards occur at constructive plates?

Volcanic eruptions, Earthquakes, Ridge Push, Shield Volcanoes

What landforms/hazards occur at transform plates?

Earthquakes

What landforms/hazards occur at destructive plates?

Volcanic eruptions, Earthquakes, Slab pull, Stratovolcano, Fold mountain

How do earthquakes form at constructive plates?

• Plates are jagged/not smooth/rough base

• Plates move move apart and drag along the mantle

• Friction builds between mantle and plates

• Plates jolt/get stuck

• Pressure builds

• Seismic waves released from focus

• Small earthquakes

How do volcanic eruptions occur at constructive plates?

• Plates move apart

• Magma slowly rises through crust

• Lava forms + cools for new rock

• Volcanic eruption

• Shield volcanoes form

How do earthquakes form at destructive plates?

• Plates are jagged/not smooth/rough base

• Plates move towards each other and collide

• Friction builds

• Plates jolt/get stuck

• Pressure builds

• Seismic waves released from focus

• Violent earthquakes

How do volcanic eruptions occur at destructive plates?

• Oceanic plates moves towards continental

• Oceanic plate subducts as its denser/heavier

• Plate sinks to mantle

• Melts to form magma

• Heat makes magma rise to surface

• Pressure builds under the earths surface

• Magma escapes through the rock

• Volcanic eruption

• Stratovolcanoes form

How do earthquakes form at transform plates?

• Plates are jagged/not smooth/rough base

• Plates move alongside each other

• Friction builds between plates

• Plates jolt/get stuck

• Pressure builds

• Seismic waves released from focus

• Violent earthquakes

Why can volcanoes not occur at transform plates?

No space for magma to rise

What is a volcano with steep sides called?

Stratovolcano

Where do stratovolcanoes form?

Destructive plate margins

Where do shield volcanoes form?

Constructive plate margins

Where and how do fold mountains form?

At destructive plate margins, 2 continental plates meet

How do we measure earthquakes?

Richter Scale

Richter Scale

A scale to measure the magnitude of an Earthquake - 1 to 10

Focus

Where the pressure is released in the cross of the earth

Epicentre

The points on the earth surface directly above the focus

Seismic waves

The energy released in an earthquake from the focus

Foreshock

Occurs before the main earthquake begins

Main shock

The main or largest earthquake

Aftershock

Occurs after the main earthquake has ended. (It’s not always smaller; could be the same size.

Does a shallow focus or deep focus cause more damage?

A shallow focus has larger impact as seismic wave energy is stronger

What is lava called once it erupts through the crust?

Magma

Why does magma rise?

It’s hot and less dense

What is the old theory for tectonic plate movement?

Convection currents

Describe convection currents

• Inner core reaches 6000

• Heat heats up the magma

• Magma rises in the mantle because it’s less dense and hot

• When it gets near the crust, the heat splits and cause it becomes sudden that it sinks back to the core

• Reheated and process repeats

How did geographers disprove convection currents?

Using modern imagen techniques - identifying currents in the mantle through x rays

What is the new theory for tectonic plate movement?

Ridge push slab pull

What is the key force in ridge push slab pull?

Slab pull

What plate margin is the slab pull at?

Destructive

What plate margin is the ridge push at?

Constructive

Primary effects

Occurs immediately after the earthquake happens (direct effect) like buildings destroyed or injuries

Secondary effects

Occurs as a result of the primary effects (indirect effect) like homelessness or landslides

Immediate response

Response within days or weeks of the disaster like search and rescue

Long term response

Response within months or years of a disaster like rebuilding homes

What is our LIC case study for earthquakes?

Gorkha, Nepal

What is our HIC case study for earthquakes?

L’Aquila, Italy

When was the Nepal earthquake?

2015

When was the Italy earthquake?

2009

What was the magnitude of the Nepal earthquake?

7.8 magnitude

What was the magnitude of the Italy earthquake?

6.3 magnitude

Nepal earthquake: Primary effects

• 8,841 killed

• 16,800 injured

• 600,000 buildings collapsed

• 7000 schools destroyed

• 26 hospitals destroyed

• Dharahara tower destroyed

Nepal earthquake: Secondary effects

• 1 million homeless

• Landslides/avalanches on Mt. Everest killed 19

• Rice seed ruined before monsoon season - food shortage, farming loss

• Tourism declined - jobs, money

Italy earthquake: Primary effects

• 308 killed

• 1500 injured

• 10-1500 buildings collapsed

• San salvatore hospital collapsed

Italy earthquake: Secondary effects

• 67,500 homeless

• Aftershocks trigger landslides

• Mudflow caused by burst water pipe in town of Paganio

Nepal earthquake: Immediate responses

• 500,000 tents provided

• Free telephone calls

• UN set up field hospitals

• Facebook launched a safety feature for users to indicate if they’re safe

Nepal earthquake: Long term responses

• Farmers taught how to repair their equipment

• Stricter building controls enforced

• Lakes and river valleys cleared of landslide material - avoid flooding

Italy earthquake: Immediate responses

• 400,000 tents provided

• Italian Red Cross searching for survivors within an hour

• Water, hot meals, tents, blankets distributed by Italian Red Cross

• Mortages, bills, TV, Electricity and gas bills suspended

Italy earthquake: Long term responses

• Students in L’Aquila given free Transport, discounts on school equipment and no paying university fees for 3 years after earthquake

• US 552.9 million aid from EU

• Pay no tax in 2010

How many died in the Nepal earthquake?

8,841

How many died in the Italy earthquake?

308

How many buildings collapsed in Nepal earthquake?

600,000

How many buildings collapsed in Italy earthquake?

10,000-15,000

How many were injured in the Nepal earthquake?

16,800

How many schools collapsed in Nepal earthquake?

7000

How many hospitals collapsed in Nepal earthquake?

26

What famous landmark collapsed during Nepal earthquake?

Dharahara tower

How many hospitals collapsed during Italy earthquake?

1 - San Salvatore

How many people were made homeless in the Nepal earthquake?

1 million

How many people were made homeless in the Italy earthquake?

67,500

How many people were killed due to the landslides/avalanches in Nepal?

Killed 19

How many tents were provided in the Nepal earthquake?

500,000

How many tents were provided in the Italy earthquake?

400,000

How do we manage hazards?

Using MPPP

Monitoring - observe/watch

Prediction - work out when hazard will occur

Protection - keeps building safe from damage

Planning - ensure everyone is prepared and knows what to do

Why is hazard management using MPPP important?

• Reduces likelihood of natural hazard becoming natural disaster

• Protects buildings or towns from damage

• Monitor natural hazard to know more about its causes/effects

MPPP - How can we monitor earthquakes?

Use seismometers to monitor pattern of activity

MPPP - How can we predict earthquakes?

Cannot be predicted until moments before

MPPP - How can we protect from earthquakes?

• Cross bracing

• Shear walls

• Shock absorbers

How do shear walls protect buildings from earthquakes?

Concrete slabs locked into the foundation and running up the building

Stabilises the building to reduce walking/swaying + sends seismic waves down to the foundation

How does shock absorbers protect buildings from earthquakes?

Made out of rubber + built into the foundation under the building

Absorb seismic waves to prevent shaking + helps build sway with shaking

MPPP - How can we plan for earthquakes?

• Prepare emergency kits

• Drop! Cover! Hold! Drill

• Evacuation practice

• Education

What is earthquake emergency kits?

• Whistle - alert people if in danger/lost

• Torch - if electrical wires/road lights go out

• First aid kit - help with injuries to prevent more injuries/deaths

Evacuation

Moving people from a dangerous to safe place

MPPP - How can we monitor/predict volcanoes?

• Tiltmeter

• Seismometer

• Thermometer

• Gas trapping bottle