Scientists are Mapping the World's Largest Volcano Reading Answers

Oct 31, 2025

The IELTS reading answers for "Scientists are Mapping the World's Largest Volcano" include 12 questions and are part of the evaluation framework for the IELTS General Reading assessment. Test takers are allotted 20 minutes to complete the reading answers related to "Scientists are Mapping the World's Largest Volcano." This section of the IELTS reading test features different question formats, such as filling in the blanks with no more than two words and selecting the correct letter.

The reading answers for "Scientists are Mapping the World's Largest Volcano" offer an in-depth look at how scientists studying the gigantic underwater volcano Tamu Massif uncovered new insights regarding its formation, utilizing sonar and magnetic analysis, despite facing challenges like shark attacks on their gear. Their research indicates that the volcano emerged quickly around 145 million years ago, likely due to both mid-ocean ridge eruptions and deep mantle plumes. For additional practice with similar reading assessments, candidates can refer to the IELTS Reading Practice Test section.

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Scientists are Mapping the World's Largest Volcano Reading Answers

(A)After 36 days of battling sharks that kept biting their equipment, scientists have returned from the remote Pacific Ocean with a new way of looking at the world's largest - and possibly most mysterious - volcano, Tamu Massif.

(B)The team has begun making 3-D maps that offer the clearest look yet at the underwater mountain, which covers an area the size of New Mexico. In the coming months, the maps will be refined and the data analyzed, with the ultimate goal of figuring out how the mountain was formed.

(C)It's possible that the western edge of Tamu Massif is actually a separate mountain that formed at a different time, says William Sager, a geologist at the University of Houston who led the expedition. That would explain some differences between the western part of the mountain and the main body.

(D)The team also found that the massif (as such a massive mountain is known) is highly pockmarked with craters and cliffs. Magnetic analysis provides some insight into the mountain's genesis, suggesting that part of it formed through steady releases of lava along the intersection of three mid-ocean ridges, while part of it is harder to explain. A working theory is that a large plume of hot mantle rock may have contributed additional heat and material, a fairly novel idea.

(E)Tamu Massif lies about 1,000 miles (1,600 kilometers) east of Japan. It is a rounded dome, or shield volcano, measuring 280 by 400 miles (450 by 650 kilometers). Its top lies more than a mile (about 2,000 meters) below the ocean surface and is 50 times larger than the biggest active volcano on Earth, Hawaii's Mauna Loa. Sager published a paper in 2013 that said the main rise of Tamu Massif is most likely a single volcano, instead of a complex of multiple volcanoes that smashed together. But he couldn't explain how something so big formed.

(F)The team used sonar and magnetometers (which measure magnetic fields) to map more than a million square kilometers of the ocean floor in great detail. Sager and students teamed up with Masao Nakanishi of Japan's Chiba University, with Sager receiving funding support from the National Geographic Society and the Schmidt Ocean Institute.

(G)Since sharks are attracted to magnetic fields, the toothy fish "were all over our magnetometer, and it got pretty chomped up," says Sager. When the team replaced the device with a spare, that unit was nearly ripped off by more sharks. The magnetic field research suggests the mountain formed relatively quickly, sometime around 145 million years ago. Part of the volcano sports magnetic "stripes," or bands with different magnetic properties, suggesting that lava flowed out evenly from the mid-ocean ridges over time and changed in polarity each time Earth's magnetic field reversed direction. The central part of the peak is more jumbled, so it may have formed more quickly or through a different process.

(H)Sager isn't sure what caused the magnetic anomalies yet, but suspects more complex forces were at work than simply eruptions from the ridges. It's possible a deep plume of hot rock from the mantle also contributed to the volcano's formation, he says. Sager hopes the analysis will also help explain about a dozen other similar features on the ocean floor, as well as add to the overall understanding of plate tectonics.

QUESTIONS 1-8

READING PASSAGE 1 HAS EIGHT PARAGRAPHS, A-H.

WHAT PARAGRAPH HAS THE FOLLOWING INFORMATION?

WRITE THE CORRECT LETTER, A-H, IN BOXES 1-8 ON YOUR ANSWER SHEET.

1. Possible explanation of the differences between parts of the mountain

Answer: C

Supporting statement: “It’s possible that the western edge of Tamu Massif is actually a separate mountain that formed at a different time... That would explain some differences between the western part of the mountain and the main body.”

Keywords: western edge, separate mountain, differences

Keyword Location: Paragraph C, lines 1–3

Explanation: The paragraph directly discusses the possible explanation for the differences between various parts of Tamu Massif, which makes paragraph C the correct answer.

2. Size data

Answer: E

Supporting statement: “Tamu Massif lies about 1,000 miles east of Japan... measuring 280 by 400 miles... 50 times larger than the biggest active volcano on Earth, Hawaii's Mauna Loa.”

Keywords: measuring, 280 by 400 miles, size, largest volcano

Keyword Location: Paragraph E, lines 1–4

Explanation: The paragraph provides detailed size data and measurements of the volcano, confirming that the correct paragraph is E.

3. A new way of looking

Answer: A

Supporting statement: “Scientists have returned... with a new way of looking at the world’s largest – and possibly most mysterious – volcano, Tamu Massif.”

Keywords: new way of looking, scientists returned

Keyword Location: Paragraph A, lines 1–2

Explanation: The statement explicitly mentions a new way of looking at Tamu Massif, which matches the question perfectly.

4. Problem with sharks

Answer: G

Supporting statement: “Since sharks are attracted to magnetic fields, the toothy fish ‘were all over our magnetometer, and it got pretty chomped up.’”

Keywords: sharks, magnetometer, chomped up, problem

Keyword Location: Paragraph G, lines 1–3

Explanation: This paragraph clearly describes the problem caused by sharks interfering with the magnetic equipment, so G is correct.

5. Uncertainty of the anomalies

Answer: H

Supporting statement: “Sager isn’t sure what caused the magnetic anomalies yet, but suspects more complex forces were at work...”

Keywords: isn’t sure, magnetic anomalies, complex forces

Keyword Location: Paragraph H, lines 1–2

Explanation: This line indicates uncertainty about the cause of magnetic anomalies, making H the right answer.

6. Equipment which measures magnetic fields

Answer: F

Supporting statement: “The team used sonar and magnetometers (which measure magnetic fields) to map more than a million square kilometers...”

Keywords: magnetometers, measure magnetic fields

Keyword Location: Paragraph F, line 1

Explanation: The paragraph mentions the instrument used to measure magnetic fields, which is the magnetometer, confirming F.

7. The start of making maps

Answer: B

Supporting statement: “The team has begun making 3-D maps that offer the clearest look yet at the underwater mountain...”

Keywords: begun, making maps, 3-D

Keyword Location: Paragraph B, line 1

Explanation: The team started creating 3-D maps, making B the correct paragraph.

8. A working theory

Answer: D

Supporting statement: “A working theory is that a large plume of hot mantle rock may have contributed additional heat and material...”

Keywords: working theory, plume, mantle rock

Keyword Location: Paragraph D, last line

Explanation: The phrase “A working theory is that…” directly matches the question, confirming D as the correct paragraph.

QUESTIONS 9-12

COMPLETE THE SENTENCES USING NO MORE THAN TWO WORDS FROM THE PASSAGE.

WRITE YOUR ANSWERS IN BOXES 9-12 ON YOUR ANSWER SHEET.

9. A large plume of ……………… rock may have contributed additional heat and material.

Answer: mantle

Supporting statement: “A working theory is that a large plume of hot mantle rock may have contributed additional heat and material...”

Keywords: plume, hot, mantle rock

Keyword Location: Paragraph D, last line

Explanation: The correct phrase is “mantle rock”, where mantle is the missing word referring to the type of rock adding heat and material.

10. Tamu Massif is a ……………...., or shield volcano.

Answer: rounded dome

Supporting statement: “It is a rounded dome, or shield volcano, measuring 280 by 400 miles...”

Keywords: rounded dome, shield volcano

Keyword Location: Paragraph E, line 2

Explanation: The passage directly states that Tamu Massif is a rounded dome, which serves as the synonym for “shield volcano.”

11. Replacing the device with a ……………… didn't help, as that unit was nearly ripped off by more sharks.

Answer: spare

Supporting statement: “When the team replaced the device with a spare, that unit was nearly ripped off by more sharks.”

Keywords: replaced, device, spare, sharks

Keyword Location: Paragraph G, lines 3–4

Explanation: The missing word is “spare”, referring to the second magnetometer that also got attacked by sharks.

12. Sager believes that the magnetic anomalies were caused by something more than …………. from the ridges.

Answer: eruptions

Supporting statement: “Sager isn’t sure what caused the magnetic anomalies yet... suspects more complex forces were at work than simply eruptions from the ridges.”

Keywords: more complex forces, eruptions, ridges

Keyword Location: Paragraph H, lines 1–2

Explanation: The phrase shows that the anomalies were caused by something more than eruptions, making that the correct answer.

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