Earthquakes often happen near volcanoes, but this is not always true. The centers of some are 1. The bottom of the sea suddenly 2. The powerful forces inside the 3break the rocks. The coast is shaken and great waves appear. These waves travel 4and rush over the land when they reach it. They are strong enough to 5houses and other buildings; sometimes they break 6than the earthquake itself. Very often fires followed the 7earthquakes. In 1906, the great earthquake at San Francisco broke the gas-pipes. The gas 8, and soon large numbers of fires were burning in the city. The water-pipes were also 9; so it was not possible to put the fires out. There was 10. The Tokyo earthquake of 11happened just before the middle of the day. People were 12on their fires at that time. When the ground shook, the fires shook too. 13were thrown on the different parts of the houses, some of which were 14. Soon 134 fires were burning in the city. What kind of building 15in an earthquake? A building with concrete walls is perhaps the best. A 16will make it even stronger. The frame holds the 17together, and the walls do not easily fall. There is 18of fire because concrete and steel do not burn. The Americans 19the results of the earthquake in San Francisco, and they are convinced that this kind of building is the 20.