Read carefully. You will answer questions about this passage in the next section.
1Deep beneath the surface of the Earth, rock is so hot that it melts and becomes a thick, flowing liquid called magma. Magma collects in underground chambers, building up enormous pressure over thousands of years. When the pressure becomes too great, the magma forces its way upward through cracks in the Earth's crust. Once it reaches the surface, it is called lava.
2A volcano is an opening in the Earth's surface through which lava, ash and gases escape. Not all volcanoes look the same. Some have gentle slopes and produce slow-moving lava, while others have steep sides and erupt with tremendous force, sending clouds of ash high into the atmosphere. The most famous eruption in history was that of Mount Vesuvius in AD 79, which buried the Roman city of Pompeii under metres of volcanic ash.
3Volcanoes are found all over the world, but they are most common along the edges of the enormous plates that make up the Earth's crust. This zone is known as the Ring of Fire and stretches around the edges of the Pacific Ocean. Countries including Japan, Indonesia and Chile all lie within the Ring of Fire and experience frequent volcanic activity.
4Although volcanoes can be extremely dangerous, they are also surprisingly useful. Volcanic soil is incredibly rich in minerals, making it some of the most fertile farmland in the world. Many communities have built their homes on the slopes of volcanoes for exactly this reason, knowing that the soil will help their crops grow. Volcanoes also create new land: the islands of Hawaii, for example, were built entirely from volcanic rock rising out of the sea over millions of years.
5Scientists who study volcanoes are called volcanologists. They use special equipment to measure changes in temperature, the movement of the ground and the release of gases, all signs that an eruption may be coming. Thanks to their work, communities living near active volcanoes can be warned in advance and evacuated to safety before disaster strikes. While it is impossible to predict exactly when a volcano will erupt, modern science has saved many lives.
Match each word to its correct meaning.