A Lecture On Earth Sciences - IELTS Listening Sample Answer
IELTS Listening section tests a candidate’s listening skills through four parts. The candidate needs to listen to the four parts properly then answer the IELTS listening questions. This topic - A lecture on earth sciences is an IELTS listening Section Four topic. It contains the following question types:
- Complete the notes
- Multiple choice
Audio Transcript
Good morning and welcome to this earth sciences lecture . We’ve been looking recently at such phenomena as earthquakes , tsunami, volcanic eruptions and other natural occurrences . Today we are going to look at a lesser known feature of the earth which is known as the supervolcano . As the name implies this is a volcano of a much larger size than what we normally imagine a volcano to be. The term super volcano has no specifically defined scientific meaning. It is used to refer to volcanoes that have generated Earth’s largest volcanic eruptions. As such, a super volcano would be one that has produced an exceedingly large, catastrophic explosive eruption and a giant caldera the , a caldera being the gigantic crater that the eruption creates. Whereas normal volcano craters are measured in the hundreds of metres, a caldera can easily be as large as 40 or 50 miles wide. Around the world there are several volcanic areas that can be considered super volcanoes such as Long Valley in eastern california towba , Toba in Indonesia and Lake Taupo in New Zealand. There are also other large calderas in japan , Indonesia, Scotland and alaska . Not all the calderas are active though.
Normal volcanoes are formed by a column of magma , rising from deep within the Earth, erupting on the surface, and hardening in layers down the sides. This forms the familiar cone-shaped mountain we associate with volcanoes. Super volcanoes, however, begin life when magma rises from the Earth’s mantle to create a boiling reservoir in the Earth’s crust. This chamber increases to an enormous size, building up colossalpressure until it finally erupts. An explosion like this could send ash, dust, and sulphur dioxide into the atmosphere, reflecting the sun’s rays and creating a cold wave lasting several years. Crops in many areas would fail and many species of animals and plants, including humans, would face extinction .
The most recent caldera-forming eruption in the US was about 650,000 years ago in the north east United States. During that eruption, ground-hugging flows of hot volcanic ash, pumice , and gases swept across an area of more than 3000 square miles . The eruption also shot a column of volcanic ash and gases high into Earth’s stratosphere . This volcanic cloud circled the globe many times and affected the Earth’s climate by reducing the intensity of solar radiation reaching the lower atmosphere and surface. Fine volcanic ash that fell downwind from the eruption site blanketed much of North America. This ash layer is still preserved in deposits as far away as Iowa, where it is a few inches thick, and the Gulf of Mexico, where it is recognizable in drill cores from the sea floor.
It is little known that lying underneath one of The United States’ largest and most picturesque National Parks, Yellowstone Park, is one of the largest super volcanoes in the world. Volcanic activity began in the Yellowstone National Park region about two million years ago. Magma rising from deep within the Earth has produced three cataclysmic eruptions more powerful than any in the world’s recorded history. The first caldera-forming eruption occurred about 2.1 million years ago. The eruptive blast removed so much magma from its subsurface storage reservoir that the ground above it collapsed into the magma chamber and left a caldera larger than the state of Rhode Island. The huge calderameasured as much as 50 miles long, 40 miles wide and hundreds of meters deep, extending from outside Yellowstone National Park into the central area of the Park.
Scientists have revealed that Yellowstone Park has been on a regular eruption cycle of 600,000 years . The last eruption was 640 000 years ago so the next is overdue. The next eruption could be 2500 times the size of the 1980 Mount St. Helens eruption. Vulcanologists have been tracking the movement of magma under the park and have calculated that in parts of yellowstone the ground has risen over point seven of a metre this century. This means the magma is rising.
geologists have called for a taskforce to be set up to consider emergency management in the event of a massive volcanic eruption, or super-eruption. Experts say such an event would have a colossal impact on a global scale.
The fallout from a super-eruption could cause a “volcanic winter”, devastating global agriculture and causing mass starvation . One past super-eruption struck at Toba in Sumatra 74 thousand years ago and is thought by some to have driven the human race to the edge of extinction. Signs from DNA suggest human numbers could have dropped to about 10,000 , probably as a result of the effects of climate change. The volcanic winter resulting from a super-eruption could last several years or decades, depending on the scale of an eruption, and according to recent computer models , could cause cooling on a global scale by 5 to 10 degrees celsius.
Questions 31-36
Complete the lecture notes below.
Write NO MORE THAN TWO WORDS OR A NUMBER for each answer.
| The Super Volcano No specifically defined scientific meaning – refers to volcanoes that have generated the Earth’s largest volcanic eruptions. Super volcano eruption form calderas. Whereas normal volcano craters are measured in the hundreds of metres, a caldera can be easily as large as 31 ______ or 50 miles wide. Super Volcano Caldera Locations: • Long Valley, Eastern California (not all active) • Toba, Indonesia • Lake Taupo, 32 ______ • Japan • Indonesia • Scotland • Alaska Normal Volcano Formation: Magma column rises from Earth, erupts and hardens down sides creating the familiar 33 ______ mountain Super Volcano Formation: Magma rises from Earth’s mantle creating a 34 ______ in the Earth’s crust. Chamber increases to enormous size, creating colossal pressure. Eruption finally forms massive caldera. Results of Super Volcano Eruption • Ash, dust and sulphur dioxide ejected, blocking the sun and creating cold waves lasting several years. Plants and animals (including humans) would die. • Most recent caldera-forming eruption happened 35 ______ years ago approximately. Ash, pumice, and gases covered more than 3000 square miles and also went high into the stratosphere to circle the Earth, affecting its temperature. Ash from this eruption still found in Iowa and in 36 ______ from the Gulf of Mexico. |
Question 31.
Answer: 40
Explanation: Following the speech, we can hear “a caldera can easily be as large as 40 or 50 miles wide.” The answer should be “40" since 50 has been given.
Also, check:
Question 32.
Answer: New Zealand
Explanation: The speaker stated, “Around the world, there are several volcanic areas that can be considered supervolcanoes such as Long Valley in eastern California towba, Toba in Indonesia and Lake Taupo in New Zealand.” therefore the answer should be New Zealand.
Question 33.
Answer: cone-shaped
Explanation: We can hear about the magma column in the lecture. The speaker mentioned, “This forms the familiar cone-shaped mountain.” Thus, the correct answer is “cone-shaped”
Question 34.
Answer: boiling reservoir
Explanation: As stated by the speaker, “when magma rises from the Earth’s mantle to create a boiling reservoir in the Earth’s crust.” Thus the answer is boiling reservoir.
Question 35.
Answer: 650,000
Explanation: The lecturer says that “The most recent caldera-forming eruption in the US was about 650,000 years ago”. Here “Approximately” and “about” have the same meaning so the correct answer is 650,000.
Question 36.
Answer: drill cores
Explanation: We can hear in the lecture that “the Gulf of Mexico, where it is recognizable in drill cores from the seafloor.” Therefore the correct answer should be drill cores.
Questions 37-40
Choose FOUR letters (A-H) and write them in any order in boxes 37-40 on your answer sheet.
According to the Earth Sciences lecture, FOUR of the following facts are NOT true.
- Yellowstone Park has previously suffered three enormous eruptions.
- The first super eruption in Yellowstone was over three million years ago.
- The first super eruption in Yellowstone park created a caldera bigger than another state of the US.
- Scientists say Yellowstone Park should erupt approximately every 600 000 years.
- The ground level of Yellowstone Park has increased by over half a metre over the last 10 years.
- A task force has been set up to plan for the possible devastation that a Yellowstone eruption would cause.
- Evidence suggests that the super-eruption at Toba caused the Earth’s population of humans to drop to about 10 000.
- A super-eruption could make the Earth’s temperature drop to 5 to 10 degrees Celsius.
Question 37.
Answer: B
Explanation: As mentioned by the speaker the first caldera-forming eruption occurred about 2.1 million years ago and not three million years ago. Therefore statement B is incorrect.
Question 38.
Answer: E
Explanation: The speaker mentions that in parts of Yellowstone the ground has risen over point seven of a meter this century. Therefore statement B is not true.
Question 39.
Answer: F
Explanation: As stated by the speaker, “geologists have called for a task force to be set up to consider emergency management in the event of a massive volcanic eruption, or super-eruption.” Thus F is incorrect.
Question 40.
Answer: H
Explanation: The speaker mentions “super-eruption……., could cause cooling on a global scale by 5 to 10 degrees celsius.” According to this H is incorrect.
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