Earthquakes Plate Tectonics

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Earthquakes Plate Tectonics


Contents

Earthquake basics

Limiting the damage

Comparing earthquake impact

A case study: The Indian Ocean earthquake

Summary activities

The key concepts covered are:Place, Space and Physical and human processes.


Earthquake basicsEarthquake basics

Be able to describe where earthquakes occur.

Understand the terms focus and epicentre.

Be able to suggest ways to measure earthquakes.

By the end of this section, you will:


Where do earthquakes occur?

Pacific Plate

North American

Plate

African Plate

Indo-Australian

Plate

Eurasian Plate

South American

PlateNazca Plate

Do the location of earthquakes form a pattern?

Earthquakes are vibrations of the earth’s crust caused by movement at plate boundaries and major fault lines. The red areas on the map are where earthquakes are most common.


Earthquakes can occur at all four major plate boundaries but the most severe earthquakes usually occur at conservative

and destructive plate boundaries.

Conservative boundary

Destructive boundary

What are earthquakes?


Destructive plate boundary


Conservative plate boundary


Epicentre and focus


The Richter scale can be used to measure the magnitude (power) of a tremor using an instrument called a seismograph.

How are earthquakes measured?

It is a logarithmic scale which means that a size ‘6’ earthquake on the Richter scale is 10 times larger than a size ‘5’ and 100 times larger than a size ‘4’.


How does a seismograph work?


The Mercalli scale rates an earthquake's magnitude based on observations of the damage it causes on a scale of 1 to 12.

The Mercalli Scale

Items shake from shelves: scale 5

Buildings collapse: scale 10


Limiting the damageLimiting the damage

Be able to identify the long and short term impacts of earthquakes.

Be able to suggest ways that the impacts of earthquakes can be reduced by humans.



What effects do earthquakes have?


Protect construct buildings and roads that withstand shaking.

Plan emergency services can practise for disasterstock-pile medicine, food, blankets etceducate the population in what to do during and after.

How can we limit earthquake damage?

water levels can change in wells and lakes foreshocks can be detected by a seismometer and a tilt meter can detect movement within rockanimals can act strangely before an earthquake.

PredictPredicting earthquakes accurately enough to evacuate people is nearly impossible but:


Planning and protecting


Which shape of building would be most

‘earthquake proof’?

Buildings in earthquake zones

strong lintels

overlapping bricks

deep foundations

What makes a building strong?


This is San Francisco in the USA.

This skyscraper has been designed and constructed to be ‘earthquake-proof’. Its wide base lowers the structure’s centre of gravity and makes it more stable.

Building in earthquake zones

San Francisco is near the San Andreas Fault and therefore the city experiences earthquakes.


Before and after responses


Comparing and contrasting earthquakes

Comparing and contrasting earthquakes

Have compared the impacts of earthquakes on a MEDC and a LEDC.

Have considered development as a key issue in earthquake response.



magnitude of the earthquake

physical landscape

time of day

building design and construction

emergency service response

GDP

education.

Which factors do you think are the most important?

Which factors are related to the wealth of the country?

How can education limit earthquake damage?

What factors affect earthquake damage?

Different factors affect the damage an earthquake causes:


Why might more people have died in

Pakistan than in LA?

Why might more people have died in

Pakistan than in LA?

How different were the immediate effects of these earthquakes?

How different were the immediate effects of these earthquakes?

What the papers say


Pakistan lies on a collision boundary between the Indian plate and the Eurasian plate.

The Indian plate is moving into the Eurasian plate at a rate of 67 mm per year. The motion causes the Himalayas to rise, as well as producing earthquakes.

Epicentre of the 2005 Pakistan earthquake.

What’s moving in Pakistan?


What’s moving in California?

The San Andreas fault is a conservative fault that runs along the West of California. Los Angeles lies very close to it.

All land west of the fault on the Pacific Plate is moving to the North-west. All land east of the fault on the North American plate is moving to the South-west.

The epicentre of the 1994 LA earthquake

The rate of slippage across California is 33-37 mm per year.


Comparing devastation


Using these photos as a guide, can you tell a story of the effects the earthquake had and how people

responded to it?

Using these photos as a guide, can you tell a story of the effects the earthquake had and how people

responded to it?

Devastation and recovery in Pakistan


Earthquake aid


Case study: the Indian Ocean earthquakeA case study:

The Indian Ocean earthquake

Understand what a tsunami is.

Understand how an earthquake in the Indian Ocean caused a tsunami and be able to state some of its impacts.



Tsunamis are tidal waves caused by underwater earthquakes. A tsunami travels at speeds between 400 and 600 mph.

The tsunami spread across the Indian Ocean affecting coastal areas of 14 countries including Indonesia, Sri Lanka, India, Bangladesh, Myanmar, The Maldives and Malaysia.

The tsunami in the Indian Ocean occurred on 26th December 2004. The earthquake measured 9.0 on the Richter Scale and occurred off the northern tip of Sumatra. Over 226,000 people are presumed to have died in the disaster. Earthquake epicentre

The Indian Ocean tsunami


10th January 2003 29th December 2004Before the tsunami. After the tsunami.

What do you think these satellite images show?

Washed away


The tsunami brought devastation to the Indonesian province of Banda Aceh but with aid and community action, people are rebuilding their lives.

Disaster, recovery and aid


What caused the tsunami?


Summary activities

Summary activities


Be confident in your knowledge of earthquakes.

Know how to use and spell important terminology relating to earthquakes.


Summary quiz


Glossary


Anagrams

Earthquakes Plate Tectonics

Documents

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