Volcanoes – Earth-shattering News - IELTS Reading Answers & Explanations
From Cambridge IELTS 04 Academic Reading Test 3 · Part 2 · Questions 14–26
Reading Passage
You should spend about 20 minutes on Questions 14-26 which are based on Reading Passage 2 on the following pages.
Volcanoes – earth-shattering news
When Mount Pinatubo suddenly erupted on 9 June 1991, the power of volcanoes past and present again hit the headlines
A Volcanoes are the ultimate earth-moving machinery. A violent eruption can blow the top few kilometres off a mountain, scatter fine ash practically all over the globe and hurl rock fragments into the stratosphere to darken the skies a continent away.
But the classic eruption - cone-shaped mountain, big bang, mushroom cloud and surges of molten lava - is only a tiny part of a global story. Vulcanism, the name given to volcanic processes, really has shaped the world. Eruptions have rifted continents, raised mountain chains, constructed islands and shaped the topography of the earth. The entire ocean floor has a basement of volcanic basalt.
Volcanoes have not only made the continents, they are also thought to have made the world's first stable atmosphere and provided all the water for the oceans, rivers and ice-caps. There are now about 600 active volcanoes. Every year they add two or three cubic kilometres of rock to the continents. Imagine a similar number of volcanoes smoking away for the last 3,500 million years. That is enough rock to explain the continental crust.
What comes out of volcanic craters is mostly gas. More than 90% of this gas is water vapour from the deep earth: enough to explain, over 3,500 million years, the water in the oceans. The rest of the gas is nitrogen, carbon dioxide, sulphur dioxide, methane, ammonia and hydrogen. The quantity of these gases, again multiplied over 3,500 million years, is enough to explain the mass of the world's atmosphere. We are alive because volcanoes provided the soil, air and water we need.
B Geologists consider the earth as having a molten core, surrounded by a semi-molten mantle and a brittle, outer skin. It helps to think of a soft-boiled egg with a runny yolk, a firm but squishy white and a hard shell. If the shell is even slightly cracked during boiling, the white material bubbles out and sets like a tiny mountain chain over the crack - like an archipelago of volcanic islands such as the Hawaiian Islands. But the earth is so much bigger and the mantle below is so much hotter.
Even though the mantle rocks are kept solid by overlying pressure, they can still slowly 'flow' like thick treacle. The flow, thought to be in the form of convection currents, is powerful enough to fracture the 'eggshell' of the crust into plates, and keep them bumping and grinding against each other, or even overlapping, at the rate of a few centimetres a year. These fracture zones, where the collisions occur, are where earthquakes happen. And, very often, volcanoes.
C These zones are lines of weakness, or hot spots. Every eruption is different, but put at its simplest, where there are weaknesses, rocks deep in the mantle, heated to 1,350°C, will start to expand and rise. As they do so, the pressure drops, and they expand and become liquid and rise more swiftly.
Sometimes it is slow: vast bubbles of magma - molten rock from the mantle - inch towards the surface, cooling slowly, to show through as granite extrusions (as on Skye, or the Great Whin Sill, the lava dyke squeezed out like toothpaste that carries part of Hadrian's Wall in northern England). Sometimes - as in Northern Ireland, Wales and the Karoo in South Africa - the magma rose faster, and then flowed out horizontally on to the surface in vast thick sheets. In the Deccan plateau in western India, there are more than two million cubic kilometres of lava, some of it 2,400 metres thick, formed over 500,000 years of slurping eruption.
Sometimes the magma moves very swiftly indeed. It does not have time to cool as it surges upwards. The gases trapped inside the boiling rock expand suddenly, the lava glows with heat, it begins to froth, and it explodes with tremendous force. Then the slightly cooler lava following it begins to flow over the lip of the crater. It happens on Mars, it happened on the moon, it even happens on some of the moons of Jupiter and Uranus. By studying the evidence, vulcanologists can read the force of the great blasts of the past. Is the pumice light and full of holes? The explosion was tremendous. Are the rocks heavy, with huge crystalline basalt shapes, like the Giant's Causeway in Northern Ireland? It was a slow, gentle eruption.
The biggest eruptions are deep on the mid-ocean floor, where new lava is forcing the continents apart and widening the Atlantic by perhaps five centimetres a year. Look at maps of volcanoes, earthquakes and island chains like the Philippines and Japan, and you can see the rough outlines of what are called tectonic plates - the plates which make up the earth's crust and mantle. The most dramatic of these is the Pacific 'ring of fire' where there have been the most violent explosions - Mount Pinatubo near Manila, Mount St Helen's in the Rockies and El Chichón in Mexico about a decade ago, not to mention world-shaking blasts like Krakatoa in the Sunda Straits in 1883.
D But volcanoes are not very predictable. That is because geological time is not like human time. During quiet periods, volcanoes cap themselves with their own lava by forming a powerful cone from the molten rocks slopping over the rim of the crater; later the lava cools slowly into a huge, hard, stable plug which blocks any further eruption until the pressure below becomes irresistible. In the case of Mount Pinatubo, this took 600 years.
Then, sometimes, with only a small warning, the mountain blows its top. It did this at Mont Pelée in Martinique at 7.49 a.m. on 8 May, 1902. Of a town of 28,000, only two people survived. In 1815, a sudden blast removed the top 1,280 metres of Mount Tambora in Indonesia. The eruption was so fierce that dust thrown into the stratosphere darkened the skies, cancelling the following summer in Europe and North America. Thousands starved as the harvests failed, after snow in June and frosts in August. Volcanoes are potentially world news, especially the quiet ones.
Questions
Questions 14–17 Matching Headings
Reading Passage 2 has four sections A-D.
Choose the correct heading for each section from the list of headings below.
i. Causes of volcanic eruption
ii. Efforts to predict volcanic eruption
iii. Volcanoes and the features of our planet
iv. Different types of volcanic eruption
v. International relief efforts
vi. The unpredictability of volcanic eruptions
Questions 18–21 Short Answers
Answer the questions below using NO MORE THAN THREE WORDS AND/OR A NUMBER from the passage for each answer.
Questions 22–26 Summary Completion
Complete the summary below.
Choose NO MORE THAN TWO WORDS from the passage for each answer.
Volcanic eruptions have shaped the earth's land surface. They may also have produced the world's atmosphere and 22. Eruptions occur when molten rocks from the earth's mantle rise and expand. When they become liquid, they move more quickly through cracks in the surface. There are different types of eruption. Sometimes the 23 moves slowly and forms outcrops of granite on the earth's surface. When it moves more quickly it may flow out in thick horizontal sheets. Examples of this type of eruption can be found in Northern Ireland, Wales, South Africa and 24. A third type of eruption occurs when the lava emerges very quickly and 25 violently. This happens because the magma moves so suddenly that 26 are emitted.
Answers & Explanations Summary
| # | Answer | Evidence | Explanation |
|---|---|---|---|
| Q14 | iii | Vulcanism, the name given to volcanic processes, really has shaped the world. Eruptions have rifted continents, raised mountain chains, constructed islands and shaped the topography of the earth Volcanoes have not only made the continents, they are also thought to have made the world's first stable atmosphere and provided all the water for the oceans, rivers and ice-caps |
Excerpt/Passage Explanation: The passage states that volcanic activity is responsible for forming the shape of the world's land, such as mountains and islands. It also explains that volcanoes created the Earth's air and all the water in the oceans and rivers. Answer Explanation: The answer identifies Section A as a part of the text that describes how volcanoes shaped the physical parts of our planet, like land, water, and air. Reason For Correctness: The correct answer is choice 'iii' because Section A focuses on how volcanic activity created the major physical features of Earth. It explains that volcanoes built the continents, raised whole mountain ranges, and created islands. Furthermore, it explains that volcanoes are responsible for creating the Earth's atmosphere (the air we breathe) and the water found in our oceans and rivers. The section highlights how these natural 'machines' are the reason the Earth has its current soil, air, and water. |
| Q15 | i | The flow, thought to be in the form of convection currents, is powerful enough to fracture the 'eggshell' of the crust into plates, and keep them bumping and grinding against each other, or even overlapping, at the rate of a few centimetres a year. These fracture zones, where the collisions occur, are where earthquakes happen. And, very often, volcanoes | Excerpt/Passage Explanation: The passage explains that the movement of hot rock inside the Earth is strong enough to break the Earth's hard outer surface into pieces. When these pieces hit or rub against each other, volcanoes are often born in those spots. Answer Explanation: The answer "i" means that Section B explains the reasons or the "why" behind how volcanoes are made. Reason For Correctness: The correct answer is correct because Section B describes the physical process that leads to volcanic activity. It uses the analogy of a soft-boiled egg to explain Earth's layers and describes how the hot material under the surface moves. This movement, called 'convection currents,' is what breaks the Earth's outer shell into pieces (plates). The section explains that when these pieces crash or rub together, it creates volcanoes. Therefore, it focuses on the 'causes' of these events. |
| Q16 | iv | Every eruption is different Sometimes it is slow Sometimes - as in Northern Ireland, Wales and the Karoo in South Africa - the magma rose faster Sometimes the magma moves very swiftly indeed |
Excerpt/Passage Explanation: The passage uses these phrases to list the different speeds and styles of volcanic events. By comparing 'slow' eruptions, 'faster' ones, and 'very swiftly' moving magma, it shows that volcanic activity comes in several different types. Answer Explanation: The answer is heading iv, which means Section C focuses on the various ways that volcanoes can erupt. Reason For Correctness: The correct answer is heading iv because Section C describes the different speeds and behaviors of volcanic eruptions. It explains that eruptions vary significantly, starting with the statement that 'every eruption is different.' The section then provides examples of 'slow' eruptions that form granite, 'faster' eruptions that create flat sheets of lava like in India or Ireland, and eruptions where magma moves 'very swiftly' to cause violent, frothy explosions. |
| Q17 | vi | But volcanoes are not very predictable. That is because geological time is not like human time | Excerpt/Passage Explanation: The passage states that it is hard to know when a volcano will erupt because they function on a very long time scale that is different from the way humans think about time. Answer Explanation: The answer means that Section D is about how we cannot easily guess or know when a volcano will explode. Reason For Correctness: The correct answer is **vi** because Section D focuses on the idea that volcanoes do not follow a schedule that humans can easily understand. It mentions that some volcanoes stay quiet for hundreds of years, making them look safe, and then explode with very little warning. This quality of being unexpected and hard to guess is described by the word 'unpredictable' or 'unpredictability.' |
| Q18 | plates / the plates / tectonic plates / the tectonic plates | tectonic plates - the plates which make up the earth's crust and mantle | Excerpt/Passage Explanation: The passage identifies the specific name "tectonic plates" for the sections that form the outer layer of our world. Answer Explanation: The answer refers to the giant pieces that join together to form the outer surface of the Earth. Reason For Correctness: The correct answer is "plates" or "tectonic plates" because the passage describes the Earth's outer shell as being split into pieces. It specifically uses the term "tectonic plates" and states that they "make up the earth's crust." Additionally, the passage connects these sections to volcanic activity by explaining that the edges of these plates are where volcanoes are often found. |
| Q19 | magma | magma - molten rock from the mantle - | Excerpt/Passage Explanation: The passage explicitly defines the word 'magma' as the melted (molten) rock that comes from the Earth's middle layer (the mantle). Answer Explanation: The answer is the specific name used by scientists for the liquid, melted rock that is found deep underground in the Earth's mantle. Reason For Correctness: The correct answer is 'magma' because the text provides a direct definition for this term in section C. It explains that 'magma' is 'molten rock from the mantle'. In English, 'molten' means melted by heat, which matches the question's focus on liquid rock. The passage uses dashes to show that 'magma' and 'molten rock' mean the same thing. |
| Q20 | ring of fire | The most dramatic of these is the Pacific 'ring of fire' where there have been the most violent explosions - Mount Pinatubo near Manila, Mount St Helen's in the Rockies and El Chichón in Mexico about a decade ago, not to mention world-shaking blasts like Krakatoa in the Sunda Straits in 1883 | Excerpt/Passage Explanation: The passage states that the Pacific area known as the 'ring of fire' is a place where very strong geological activity and explosions occur. Answer Explanation: The answer identifies the specific name used for the area around the Pacific Ocean known for frequent earthquakes and volcanic eruptions. Reason For Correctness: The correct answer is 'ring of fire' because the passage explains how volcanoes and earthquakes happen along the edges of tectonic plates. It identifies the area in the Pacific as the most 'dramatic' or impressive example of these active zones. |
| Q21 | 600 / 600 years / for 600 years | In the case of Mount Pinatubo, this took 600 years | Excerpt/Passage Explanation: The passage confirms that for Mount Pinatubo, the quiet time before the pressure built up enough for another eruption was 600 years. Answer Explanation: The answer states that there was a period of 600 years when Mount Pinatubo was not active and did not erupt. Reason For Correctness: The correct answer is located in the section discussing how volcanoes can remain quiet for long periods. The passage explains that lava cools into a hard 'plug' that stops eruptions until the pressure underneath becomes too strong to hold back. It specifically mentions that for Mount Pinatubo, this process of being blocked and staying quiet lasted for 600 years. |
| Q22 | water / the water / oceans / the oceans | Volcanoes have not only made the continents, they are also thought to have made the world's first stable atmosphere and provided all the water for the oceans, rivers and ice-caps | Excerpt/Passage Explanation: The passage states that scientists believe volcanoes created both the air we breathe (the atmosphere) and all the water on Earth, such as the water found in the oceans. Answer Explanation: The answer is water or the oceans. This tells us that volcanoes are responsible for creating the earth's water and large bodies of water like oceans. Reason For Correctness: The correct answer is found in the first section of the text. It explains that volcanoes provided the earth with its first steady atmosphere and all the water used in the oceans and rivers. This matches the summary's structure, which mentions that eruptions may have produced the atmosphere as well as another element, which the passage identifies as water. |
| Q23 | lava / magma / molten rock | Sometimes it is slow: vast bubbles of magma - molten rock from the mantle - inch towards the surface, cooling slowly, to show through as granite extrusions | Excerpt/Passage Explanation: The passage explains that bubbles of hot, liquid rock called magma move slowly and turn into a type of hard rock called granite when they cool. Answer Explanation: The answer refers to the very hot, liquid rock that moves under the Earth's surface. Reason For Correctness: The correct answer is correct because Section C describes a process where 'magma' or 'molten rock' moves very slowly ('inch towards the surface') and cools to become 'granite extrusions.' An 'extrusion' or 'outcrop' is rock that shows on the surface. These terms explain that the liquid rock is what moves and eventually forms the granite mentioned in the summary. |
| Q24 | India / western India | Sometimes - as in Northern Ireland, Wales and the Karoo in South Africa - the magma rose faster, and then flowed out horizontally on to the surface in vast thick sheets. In the Deccan plateau in western India, there are more than two million cubic kilometres of lava, some of it 2,400 metres thick, formed over 500,000 years of slurping eruption | Excerpt/Passage Explanation: The passage explains that in places like Northern Ireland, Wales, South Africa, and western India, hot liquid rock from deep in the earth came up quickly and covered the land in heavy layers. Answer Explanation: The answer is a location (a country or part of a country) where volcanoes once created very thick layers of rock on the ground. Reason For Correctness: The correct answer is found in the section of the text describing volcanic eruptions where magma stays liquid and spreads out into 'vast thick sheets'. The text lists Northern Ireland, Wales, and South Africa as examples. It then mentions the Deccan plateau in western India as another location with massive amounts of this thick lava, making it the missing part of the list in the summary. |
| Q25 | explodes | Sometimes the magma moves very swiftly indeed. It does not have time to cool as it surges upwards. The gases trapped inside the boiling rock expand suddenly, the lava glows with heat, it begins to froth, and it explodes with tremendous force | Excerpt/Passage Explanation: The passage says that when hot liquid rock moves very quickly, it stays hot and the gases inside grow fast. This makes the rock turn into bubbles and then blow up with a lot of power. Answer Explanation: The answer "explodes" means to burst or blow up suddenly and with great force. Reason For Correctness: The correct answer is found in the section describing different speeds of magma movement. When magma moves very fast, the gases inside it cause a reaction. The passage explains that in these fast-moving cases, the lava becomes bubbly and then bursts with a lot of power. The word 'explodes' is used in the text to describe this specific action when the eruption is very fast and strong. |
| Q26 | gases / the gases / trapped gases / gasses / the gasses / trapped gasses | The gases trapped inside the boiling rock expand suddenly, the lava glows with heat, it begins to froth, and it explodes with tremendous force | Excerpt/Passage Explanation: The passage explains that when the liquid rock (magma) moves very quickly, the gases inside it expand fast, making it bubble up and explode with a lot of power. Answer Explanation: The answer refers to the substances (like air or steam) that are held inside the hot, liquid rock and are released or expand quickly during an explosion. Reason For Correctness: The correct answer is 'gases' or 'trapped gases' because the passage explains that when magma moves very fast, it doesn't have time to cool down. Instead, the gases that are stuck inside the hot rock expand very quickly. This quick expansion is what causes the volcano to explode with great power. The passage uses the phrase 'gases trapped' to describe what is inside the boiling rock before the explosion. |