Reading Passage 1
You should spend about 20 minutes on Questions
1–12 which are based on Reading Passage 1 below.
Scientists Are Mapping the World's Largest Volcano
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.
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.
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.
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.
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.
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.
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.
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.
Reading Passage 1 has ten paragraphs A-H.
Which paragraph contains the following information?
Choose the most suitable paragraph headings from the list of headings and 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 ____
2. Size data ____
3. A new way of looking _____
4. Problem with sharks _____
5. Uncertainty of the anomalies _____
6. Equipment which measures magnetic fields _____
7. The start of making maps _____
8. A working theory _____
Complete the sentences below.
NO MORE THAN TWO WORDS from the passage for each answer.
Write your answers in boxes 9-12 on your answer sheet.
9. A large plume of __________ rock may have contributed additional heat and material.
10. Tamu Massif is a __________or shield volcano.
11. Replacing the device with a __________ idn't help, as that unit was nearly ripped off by more sharks.
12. Sager believes that the magnetic anomalies were caused by something more than __________from the ridges