Presentation on theme: "1A2 Geography 10 th February 2015 Objectives: To introduce students to the causes and effects of earthquake activity. To briefly explain measures taken."— Presentation transcript:
1A2 Geography 10 th February 2015 Objectives: To introduce students to the causes and effects of earthquake activity. To briefly explain measures taken to limit the impact of possible earthquake activity in the future.
Homework: During the mid-term break, you will complete a poster, explaining: (i) How volcanoes are formed, and how volcanic eruptions occur. OR (ii) The causes of earthquakes, and the impact earthquake activity has on a region.
What is an earthquake? Earthquakes Earthquakes are sudden tremors or vibrations in the Earth’s crust.
What causes earthquakes? fault lines When plates collide or slide past one another, pressure can build up along fault lines. The sudden release of this pressure causes an earthquake.
Earthquakes focus The point in the Earth’s crust where an earthquake begins is called the focus. epicentre The point on the surface of the Earth directly above the focus is called the epicentre. (See image, page 71.) Tremors Tremors (vibrations) are strongest at the epicentre.
Earthquakes: The Epicentre The greatest damage caused by an earthquake occurs close to the epicentre. The strength of an earthquake decreases with distance from it.
Earthquakes: Aftershocks aftershocks A major earthquake may be followed by a series of smaller tremors – these are called aftershocks.
Seismologists, Seismographs & the Richter Scale. Seismologists Seismologists are the men and women who study earthquake activity. Seismographs Seismographs are used to measure tremors in the Earth’s crust. (See image, page 72.) Richter Scale The Richter Scale is used to represent the strength of an earthquake.
Earthquakes: The Richter Scale The scale ranges between 1 and 12. Each unit is ten times stronger than the one before. For example, an earthquake measuring 4.5 on the Richter Scale is ten times stronger than one measuring 3.5.
Damage caused by an earthquake. Deaths. Destruction of buildings, and infrastructural networks – such as bridges and roads. – This can present difficulty for relief efforts. Damage to electricity and gas supplies can cause fires. Damage to water supplies and sewers can cause health problems and lead to the spread of disease.
Damage caused by an earthquake. Trigger landslides and avalanches. TSUNAMIS TSUNAMIS – underwater earthquakes can lead to the creation of enormous waves (tidal waves). These can cause total devastation if they crash on to the coast of a region. (We will learn more about this during the next class, while studying the 2011 earthquake off the coast of Japan.)
Reducing the damage A number of steps can be taken to reduce the damage caused by future earthquakes. 1.Construct earthquake resistant buildings. 2.Study earthquakes, paying particular attention to patterns, frequency and locations, to attempt to determine when and where one might occur again.
1A2 Geography 10 th February 2015 Objectives: To introduce students to a case study on a major earthquake in an Asian country.
Damage caused by earthquakes. During our last lesson, we discussed the kind of damage that can be caused by an earthquake. Can you remember what was mentioned? 2011 – earthquake off the coast of Japan. Affects of this to be underlined during today’s lesson.
Japan This is a nation located in the Pacific Ocean, to the east of continental Asia. It consists of a number of islands. (See image, page 73.) The country’s capital is Tokyo, and it has a population of approximately 127.3 million people. Japan is one of the most technologically advanced countries in the world.
Japan Japan is located on a destructive plate boundary, where the Eurasian plate is colliding with the Pacific plate. (See map, page 66.) Due to this, it is prone to earthquake activity. In 2011, an earthquake off the coast of Japan created a tsunami (tidal wave) that crashed on the east coast of the country.
2011Tsunami in Japan https://www.youtube.com/watch?v=5P3Iz- MFu4A https://www.youtube.com/watch?v=5P3Iz- MFu4A https://www.youtube.com/watch?v=Rwotkwg 5y9k https://www.youtube.com/watch?v=Rwotkwg 5y9k
Japan: 2011 Earthquake. 11 th March 2011. Measuring 8.9 on the Richter Scale. The most powerful earthquake to hit Japan in recorded history. Created a tsunami that reached heights of over 40 metres (131 feet) in some places.
Japan: 2011 Earthquake - Affects The tsunami caused extensive damage to property. 130,000 buildings collapsed. One million were damaged. Thousands of people were displaced. Almost 4½ million homes in the north were left without electricity and water.
Japan: 2011 Earthquake - Affects There was considerable loss of life. According to the civil authorities, more than 15,000 people died.
Japan: 2011 Earthquake - Affects This natural disaster caused serious destruction to industry, which had a negative effect on the environment. The nuclear plant at Fukushima Daiichi was damaged. Radioactive material was discharged. Plants & animals effected. People evacuated from their homes.
Japan: 2011 Earthquake – The Cost It has been estimated that the earthquake and tsunami created approximately €200 million worth of damage, making it the most expensive natural disaster ever.