What Makes Them Blow: Matching Headings
You are going to read an article about volcanoes. Choose from the list (A-H) the sentence which best summarizes each part (1-6) of the article. There is one extra sentence which you do not need to use. There is an example at the beginning (0).
A Some people ignored the warnings and died.
B If the flow is not fast the volcano is not usually dangerous.
C The earth’s plates collide and the friction melts the rock.
D The majority of these dangerous volcanoes are in a specific area.
E An ancient, sleeping giant suddenly woke up and exploded.
F Signs of approaching disaster can be interpreted by scientists.
G Because of scientists’ increased capabilities, many lives were saved.
H Larger populations mean increased danger, but scientists can help.
When 15,000 worried Americans were ordered to leave Clark Air Base in the Philippines recently, they didn’t know what to think.Were they in real danger or were they victims of a false alarm? Within 48 hours, they had the answer, Nearby Mount Pinatubo, an active volcano that had been resting quietly for more than 600 years, suddenly erupted in a series of explosions that sent steam and ash 30 kilometres into the sky.
Pieces of rock and ash rained down on the surrounding countryside and a giant mushroom cloud was visible 100 kilometres away. Thanks in advance warnings, there were very few casualties but, fearing bigger explosions, tens of thousands of people had to leave their homes. The speedy action of the government showed the improving ability of scientists to detect whether volcanoes are about to erupt.
A week before Mount Pinatubo exploded, Mount Unzen in Japan erupted. This time there were more people killed, but they were mostly journalists and scientists drawn to the mountain by the warnings of an eruption. Residents in the surrounding areas had been taken to safety. They may have to stay away for a long time as Mount Unzen continues to erupt.
Both Pinatubo and Unzen lie along what is known as the Ring of Fire. This is a half-circle that runs around the rim of the Pacific Ocean through Asia, North America and South America. This ring contains three quarters of the earth’s 540 active volcanoes.
The number of eruptions these days is not abnormal, but human populations near these active mountains have been growing rapidly. The volcanoes are now becoming a serious threat to people. Some scientists believe that Mount Fuji has entered a period of activity, bringing with it the worrying thought of a giant eruption only 100 kilometers from Tokyo. But scientists are hopeful that they will be able to predict most major eruptions, and their record is increasingly impressive.
Since 1980, Mount St Helens in America has erupted 22 times, and 19 of those were predicted by scientists. There have also been warnings before eruptions of the Redoubt Volcano in Alaska, which roared into life in 1989. Unlike earthquakes, which often happen without warning, approaching volcanic eruptions generally signal their arrival. Before an explosion, instruments can detect a series of tremors in the mountain which tells scientists that liquid rock, called magma, is coming up from deep inside the earth.
The magma rises slowly, forcing open cracks that serve as pipelines to the surface. If the magma is fairly liquid, it produces a gentle, low-speed flow that is rarely a threat to humans. The Ring of Fire volcanoes are much more dangerous because they tend to explode violently. Scientists, therefore, keep a very watchful eye on them.
1.G; 2.A; 3.D; 4.H; 5.F; 6.B