9781422287835

9

EARTHQUAKES, LANDSLIDES, VOLCANOES, AND AVALANCHES Simply being aware is one of the keys for coping with natural disasters. Elite soldiers are always alert, watching for both the potential dangers of the region and the correct course of action to take. Earthquakes Earthquakes are impossible to predict, and can have a number of different classifications—tectonic, volcanic, and artificially produced. No place on Earth is free from the danger of an earthquake. Most earthquakes occur at the edges of tectonic plates. Plates either slide against each other, or one under the other, but there are plenty of examples of earthquakes that do not occur at the edges of plates. The danger of an earthquake is usually its effect on man-made structures or the triggering of such things as landslides and tidal waves (tsunamis). Recording an earthquake The Richter Scale is a means of measuring the strength of an earthquake. It was introduced in 1935, and named after Charles Frances Richter, who invented it. It is based on a rating system of 1-10, 1 being a very insignificant earth tremor, 10 a huge quake of catastrophic proportions. There has never been a quake that has registered more than 9 on the scale. Lava generally flows slowly but, with a heavy emission and a steep slope, it can reach speeds of 14 miles per hour (22 km/h).