Earthquakes. These icons indicate that teacher s notes or useful web addresses are available in the Notes Page.

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1 Earthquakes These icons indicate that teacher s notes or useful web addresses are available in the Notes Page. This icon indicates the slide contains activities created in Flash. These activities are not editable. For more detailed instructions, see the Getting Started presentation. 1 of 44

2 Learning objectives 2 of 44 What are earthquakes and where do they occur? What causes earthquakes? How are earthquakes measured? What is the difference between the epicentre and the focus? How can we limit the damage caused by earthquakes? Pakistan earthquake October 2005 What is a tsunami?

3 What are earthquakes? 3 of 44 Earthquakes are vibrations caused by earth movements at plate boundaries and at major fault lines (cracks in the earth s surface). They can occur at all four major plate boundaries but the most severe earthquakes are normally found at conservative and destructive plate boundaries. conservative destructive

4 Destructive plate boundary 4 of 44

5 Conservative plate boundary 5 of 44

6 Learning objectives 6 of 44 What are earthquakes and where do they occur? What causes earthquakes? How are earthquakes measured? What is the difference between the epicentre and the focus? How can we limit the damage caused by earthquakes? Pakistan earthquake October 2005 What is a tsunami?

7 Why do earthquakes happen? 7 of 44

8 Learning objectives 8 of 44 What are earthquakes and where do they occur? What causes earthquakes? How are earthquakes measured? What is the difference between the epicentre and the focus? How can we limit the damage caused by earthquakes? Pakistan earthquake October 2005 What is a tsunami?

9 How can we measure earthquakes? 9 of 44 The Richter Scale This measures the magnitude of a tremor (how powerful it is) using an instrument called a seismograph. On the Richter Scale, magnitude is expressed in whole numbers and decimal fractions. Although the Richter Scale has no upper limit, the largest earthquake ever recorded was in 1960 in Chile. It measured 9.5 on the Richter Scale. It is a logarithmic scale which means that a size 6 on the Richter Scale is 10 times larger than a size 5 and 100 times larger than a size 4.

10 How can we measure earthquakes? 10 of 44 The Japanese earthquake in Kobe (September 1995) measured 7.2 on the Richter Scale. The Greek earthquake (June 1995) measured 6.2 on the Richter Scale. How many times greater was the Japanese earthquake? The Japanese earthquake was 10 times more powerful than the Greek earthquake.

11 A seismograph 11 of 44

12 Mercalli Scale 12 of 44 The Mercalli scale measures how much damage is caused by the earthquake based on observations. Mercalli Scale It is measured on a scale between 1 and 12.

13 Activity 13 of 44 Design your own cartoon based on the Mercalli Scale descriptions below. I Felt by almost no one. II Felt by very few people. III Tremor noticed by many, but they often do not realise it is an earthquake. IV Felt indoors by many. Feels like a truck has struck the building. V Felt by everyone; many people are awakened. Swaying trees and poles may be observed. VI Felt by all; many people run outdoors. Furniture is moved. VII Everyone runs outdoors. Poorly built structures considerably damaged. Slight damage elsewhere. VIII Specially designed structures damaged slightly, others collapse. IX All buildings considerably damaged, many shift off foundations. Noticeable cracks in the ground. X Many structures destroyed. Ground badly cracked. XI Almost all structures fall. Bridges wrecked. XII Total destruction. Waves seen on ground surfaces.

14 Learning objectives 14 of 44 What are earthquakes and where do they occur? What causes earthquakes? How are earthquakes measured? What is the difference between the epicentre and the focus? How can we limit the damage caused by earthquakes? Pakistan earthquake October 2005 What is a tsunami?

15 Epicentre and focus 15 of 44 The focus is the point at which the rock moves. Seismic waves start at the focus. The epicentre is directly above the focus on the earth s surface.

16 Epicentre and focus 16 of 44

17 Epicentre and focus 17 of 44 Focus Epicentre An earthquake has occurred along this fault line. Match the letter with the correct label.

18 Epicentre and focus 18 of 44 An earthquake has occurred in this area. Which area (the town or the forest) will receive the stronger earthquake? Which area will receive more damage from the earthquake?

19 Epicentre and focus 19 of 44 If the epicentre of an earthquake is at A, which settlement will be damaged the most? Give reasons for your answer.

20 Learning objectives 20 of 44 What are earthquakes and where do they occur? What causes earthquakes? How are earthquakes measured? What is the difference between the epicentre and the focus? How can we limit the damage caused by earthquakes? Pakistan earthquake October 2005 What is a tsunami?

21 How can we limit earthquake damage? 21 of 44 predict plan protect water levels can rise in wells and lakes because of cracks in the rock a tiltmeter can check any movement within the rocks Predict foreshocks before the main quake can be detected by a seismometer animals can act strangely before the earthquake

22 How can we limit earthquake damage? 22 of 44 Plan and protect

23 How can we limit earthquake damage? 23 of 44 Plan and protect What should people pack in their emergency kit? Design a poster reminding people what to do in an earthquake.

24 Building regulations in earthquake zones 24 of 44 What other measures would make buildings less likely to collapse in an earthquake?

25 Buildings in earthquake zones 25 of 44 Which shape of building would be most earthquake proof? Explain your answer.

26 Building in earthquake zones 26 of 44 This is San Francisco in the USA. San Francisco is near the San Andreas Fault and therefore the city experiences earthquakes. This skyscraper has been built to be earthquake-proof. Its wide base lowers the centre of gravity of the building and makes it more stable.

27 Sky s the limit! 27 of 44 This is Sky Tower in Auckland, New Zealand. Sky Tower is the tallest tower (328 metres) in the Southern Hemisphere. It weighs 21 million kilos (20,000 tonnes), which is equivalent to 6,000 elephants! Auckland is in an earthquake zone and so the tower is constructed from a high strength, high performance concrete. Sky Tower's foundations go down more than 15 metres.

28 Factors affecting the damage caused by earthquakes 28 of 44 size of the earthquake emergency services building design and construction time of day education physical landscape 1) Which factor/s do you think is/are the most important? 2) Which factors are related to the wealth of the country? 3) How can the education of the population affect the amount of damage caused by an earthquake?

29 Factors affecting the damage caused by earthquakes 29 of 44 Read the following two slides. Compare the earthquake in Los Angeles (94) with the earthquake in Turkey (99) using the following table (you will need an atlas to help with your research). number of deaths size of the earthquake time of day emergency services building design and construction education GNP (wealth) Los Angeles Turkey

30 Los Angeles earthquake (1/94) 30 of 44

31 Turkey earthquake (8/99) 31 of 44

32 Learning objectives 32 of 44 What are earthquakes and where do they occur? What causes earthquakes? How are earthquakes measured? What is the difference between the epicentre and the focus? How can we limit the damage caused by earthquakes? Pakistan earthquake October 2005 What is a tsunami?

33 Pakistan earthquake 33 of 44 On the 8 th October 2005, a devastating earthquake hit Pakistan. The earthquake registered 7.6 on the Richter Scale. The devastation was huge. Experts believe the damage will take decades to repair.

34 Effects of the earthquake 34 of 44 More than 87,000 people died in the earthquake. It is believed that tens of thousands were injured. 3 million people were left homeless. Most of these had to struggle through the cold winter months in basic tents. It was only thanks to help provided by the government and aid agencies that thousands more did not die from cold or disease.

35 Why do earthquakes occur in Pakistan 35 of 44 Pakistan lies to the west of India and is on a collision plate boundary between the Indian plate and the Eurasian plate. Millions of years ago, these two plates collided to produce the Himalayas. The Indian plate is still moving into the Eurasian plate at a rate of 67 mm per year. This is causing the mountains to rise higher as well as producing earthquakes. Click play to see the effect a collision plate boundary has on the landscape.

36 Causes of devastation 36 of 44 One of the reasons why there was so much devastation was the poor quality of the buildings in the area. Many of the village buildings were made from stones laid together using low-grade cement, mud or sometimes even laid dry. Pakistan is not a rich country and most people did not have the money to build expensive, high-quality structures. 60% of the buildings in the towns were made from cheap stone masonry blocks, held together by low-grade mortar. Over half of these buildings collapsed in the earthquake, causing most deaths.

37 Earthquake proofing 37 of 44 Richer, industrialized countries have been able to employ advanced building techniques to minimize the devastation caused by earthquakes. These techniques are very expensive. High demand for housing in Pakistan and poor economic conditions, has meant most houses have been poorly constructed often by the occupants themselves. However, since the earthquake, the Pakistani government has introduced a new building code. It includes designs and details about how to make buildings more resistant to earthquakes.

38 Earthquake aid 38 of 44 Due to the remote location of the earthquake, many people were left stranded without help. Aid agencies and the Pakistani government needed to get emergency aid to people using helicopters. Emergency aid is short-term, it aims to supply people with the essentials they need to survive. Aid agencies have to prioritize what type of aid is the most urgently needed.

39 Earthquake aid 39 of 44

40 The future for Pakistan 40 of 44 The Pakistani government promised money to those that lost their homes. However, rebuilding after an earthquake can be difficult as often there is little infrastructure, tools are in short supply and there are few suitable sites for building. Rebuilding will offer Pakistan the chance to improve the quality of its schools and hospitals by building safer and better equipped structures but long-term recovery will be a very slow process. The devastating impact of the earthquake will have many long lasting effects on this region.

41 Learning objectives 41 of 44 What are earthquakes and where do they occur? What causes earthquakes? How are earthquakes measured? What is the difference between the epicentre and the focus? How can we limit the damage caused by earthquakes? Pakistan earthquake October 2005 What is a tsunami?

42 SE Asian tsunami December of 44 Tsunamis are tidal waves triggered by underwater earthquakes. The rate of travel of a tsunami is between miles per hour. The tsunami in SE Asia occurred on the 26 th December The earthquake measured 9.0 on the Richter Scale and occurred off the northern tip of Sumatra. The tsunami spread across the Indian Ocean and hit coastal areas of Sri Lanka, India, Bangladesh, Myanmar, Indonesia and Malaysia. The death toll is believed to be 290,000.

43 Where was the tsunami? 43 of 44

44 What caused the tsunami? 44 of 44