For questions 9-16, read the text below and think of the word which best fits each space. Use only one word in each space.
Mount Etna is Europe’s tallest active volcano (9)… stands almost 11,000ft (10)… sea level, looming over the whole Italian island of Sicily. It has been active for thousands of years, although its first eruption of modern times was thought to (11)… in 475 BC. Eruptions are rarely dangerous, but they can kill. In 1669 Etna’s most deadly moment came, when a series of blasts killed 20,000 people and destroyed the town of Catania. (12)… the danger farmers decided to stay in the area as the constant eruptions made the ground fertile. Etna posed another serious threat when in 1992 lava streams headed (13)… Zafferana, a town of 7,000 people. Italian and U.S. soldiers demonstrated spectacular skills when explosions to divert the flow (14)… used to control lava. Volcanic eruption is not (15)… hazardous due to lava but also ash clouds which can cause problems for aircraft. The immense ash clouds that erupted from Iceland’s volcano in 2010 created chaos for the airline industry. Since (16)…, a number of ash detection systems have been created to make flying around volcanic sites safer.