- Passage-1: My Nephew
- Passage-2: Bu-cola
- Passage-3: Yusri and Yusra
- Passage-4: Mother
- Passage-5: Pangolins
- Passage-6: Earthquakes
- Passage-7: When Your Time Comes
- Passage-8: Collecting Fossils
- Passage-9: The Bicycle
- Passage-10: The Egg and the Bottle
- Passage-11: Sasha’s Night Alone
- Passage-12: About The Cat
- Passage-13: Isle Of Jormuguar
- Passage-14: Shoes: Taking One Step at A Time
Passage 6 - Earthquakes
Read the following passage carefully.
[1]
You probably know that Earth is not a solid rock, but made of layers. One way to think about these layers is to imagine an egg. An egg has three layers: a shell, the white middle layer, and a yolk. Earth has three main layers too. The top layer is called the crust, and this is where we live. Like the shell of an egg, it is the thinnest of the layers. However, unlike an egg’s shell the thickness of the Earth’s crust can vary greatly. Where there are mountains, it may be seventy kilometres thick, but at the bottom of the sea it may be as thin as just 5 kilometres. The Himalayas is the tallest mountain range in the world, so this is where the crust is the thickest.
[2]
Underneath the crust is the mantle. This is like the white of the egg. The mantle is approximately 3000 kilometres thick and consists of rock that is so hot it has more or less melted. Unlike the egg’s yolk, Earth’s core has 2 parts. The outer core is a 2300 kilometre zone of liquid rock, while the inner core is a solid iron ball measuring 1200 kilometres in diameter. It is this that gives Earth its magnetic field.
[3]
Earthquakes are caused when parts of the crust move suddenly. This happens because the crust is made of separate pieces, rather like a jigsaw puzzle. Scientists call these pieces tectonic plates and they float on top of the soft rock in the mantle and move very slowly. Some plates move away from each other, some push into each other, and some slide past each other. The direction in which they are moving determines whether volcanoes, mountains or earthquakes occur respectively.
[4]
Earthquakes are caused by tectonic plates sliding past each other. The edges of the plates are rough and uneven. Sometimes, the edges of two plates get stuck and the force of the moving plates trying to push past each other builds up. Eventually, this causes the rocks along the stuck edges to break and move suddenly. Scientists estimate that around 8000 earthquakes happen every day! However, in an average year, less than a hundred quakes actually cause harm or damage. As a result, most go unnoticed.
[5]
When a strong quake happens, the ground shakes violently and can cause buildings to collapse, pipelines to break and overhead cables to come down. Roads may become blocked, making it difficult for people to survive or be rescued. Earthquakes can destroy entire towns, yet they do not last long and most are over in less than a minute. Only the very biggest last as long as five minutes.
[6]
This century has seen several large earthquakes, with one of the deadliest occurring beneath the Indian Ocean in December 2004 that resulted in a very powerful and destructive tsunami – a series of powerful and immense ocean waves. According to some reports, the waves reached a height of 30 feet (9 metres) or more when they hit the shore. This quake claimed the lives of around a quarter of a million people in twelve different countries.
[7]
It is important to understand, however, that the actual movement of the ground during an earthquake seldom causes death or injury. The danger comes from what happens next: collapsing buildings, flying glass, falling objects, fires, gas leaks, exposed electrical cables, etc. One of the most destructive earthquakes in recorded history was the 1556 Shaanxi earthquake, which happened on 23 January 1556 in Shaanxi, China. It resulted in the death of 830,000 people. Many of these deaths were due to the collapse of their dwellings. The deadliest earthquake in the 20th century was the 1976 Tangshan earthquake, in which about 655,000 people were killed.
[8]
The most powerful earthquake ever measured on a seismograph was the 1960 Chilean earthquake. It recorded 9.5 magnitude on 22 May 1960. Its epicenter was near Cañete, Chile. The next most powerful earthquake was the one in 1964, which was centered in Prince William Sound, Alaska.
[9]
The most serious damage by earthquakes occur if it happens near heavily populated areas, or in the ocean where it creates deadly tsunamis that can affect communities many thousands of kilometres away. Lax and unenforced seismic building codes are another reason for the severity of earthquake damage.
[10]
We cannot stop natural earthquakes from happening but we can significantly lessen their effects by identifying hazards, building earthquake-proof structures, and educating the public on earthquake safety. Other steps that can be taken include identifying hazards such as heavy objects and moving them to places where they won’t cause damage if they fall. In earthquake prone areas, heavy objects should be kept on the floor, or if on a shelf, at the lowest level. Bookshelves can be anchored to the wall. Besides, safety film can be applied to windows and glass doors to prevent injuries from flying glass.
Questions
Answer the following questions.
From paragraph 1
1. What object does the writer compare the Earth with?
2. Why is the Earth compared to an egg?
3. Which one word in this paragraph means ‘differ’?
From paragraph 2
4. How thick is the Earth’s mantle?
5. What is the cause of the magnetic field of the Earth?
From paragraph 3
6. What are tectonic plates?
7. Why do volcanoes, mountains or earthquakes occur?
From paragraph 4
8. Why are most earthquakes not noticed?
From paragraph 5
9. Write three destructive consequences of earthquakes.
From paragraph 6
10. What is a tsunami?
11. Pick out and write down a four-word phrase that could replace the word ‘killed’.
12. Pick out and write down a three-word phrase that shows the earthquake beneath the Indian Ocean affected a wide area.
From paragraph 7
13. What was the main cause of thousands of people dying as a result of the earthquake in 1556 in Shaanxi, China?
From paragraph 8
14. What do you think is the meaning of epicentre?
From paragraph 9
15. Write down three causes of the severe damage caused by earthquakes.
From paragraph 10
16. Write down any four steps that can be taken to lessen the damage caused by earthquakes.
Answer Scheme
From Paragraph 1
1. What object does the writer compare the Earth with?
The writer compares the earth to an egg.
2. Why is the Earth compared to an egg?
An egg has three layers: a shell, the white middle layer, and a yolk. Earth has three main layers too – crust, mantle and core.
3. Which one word in this paragraph means ‘differ’?
The word is ‘vary’.
From Paragraph 2
4. How thick is the Earth’s mantle?
The Earth’s mantle is 3000 kilometres thick.
5. What is the cause of the magnetic field of the Earth?
The cause of the magnetic field of the Earth is the inner core of the Earth that is made of solid iron.
From paragraph 3
6. What are tectonic plates?
Pieces of the Earth’s crust are called tectonic plates.
7. Why do volcanoes, mountains or earthquakes occur?
Volcanoes occur when tectonic plates of the Earth move away from each other. Mountains form when the tectonic plates push into each other. Earthquakes happen when the tectonic plates slide past each other.
From paragraph 4
8. Why are most earthquakes not noticed?
Most earthquakes go unnoticed because in an average year, less than a hundred quakes actually cause harm or damage.
From paragraph 5
9. Write three destructive consequences of earthquakes.
Earthquakes can cause buildings to collapse, pipelines to break and overhead cables to come down.
From paragraph 6
10. What is a tsunami?
A tsunami is a series of powerful and immense ocean waves.
11. Pick out and write down a four-word phrase that could replace the word ‘killed’.
The phrase is “claimed the lives of”
12. Pick out and write down a three-word phrase that shows the earthquake beneath the Indian Ocean affected a wide area.
The phrase is “twelve different countries”
From paragraph 7
13. What was the main cause of thousands of people dying as a result of the earthquake in 1556 in Shaanxi, China?
The main cause of thousands of people dying as a result of the earthquake in 1556 in Shaanxi, China was the collapse of their dwellings.
From paragraph 8
14. What do you think is the meaning of epicentre?
The epicentre of an earthquake is the point from where the Earthquake is initiated.
From paragraph 9
15. Write down three causes of the severe damage caused by earthquakes.
High population, tsunamis and not enforcing seismic building codes are the reasons for the severity of earthquake damage.
From paragraph 10
16. Write down any four steps that can be taken to lessen the damage caused by earthquakes.
Any four of the following:
1. Identifying hazards and moving them to places when they won’t cause damage it they fall.
2. Building earthquake-proof structures
3. Educating the public on earthquake safety.
4. Bookshelves can be anchored to the wall.
5. Safety film can be applied to windows and glass doors to prevent injuries from flying glass.
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