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