Every year earthquakes are responsible for a large number of deaths and a vast amount of destruction in various parts of the world. Most of these damaging earthquakes occur either in a narrow belt which surrounds the Pacific Ocean or in a line which extends from Burma to the Alps in Europe. Some of the destruction is caused directly by the quake itself. One example is the collapse of buildings as a result of vibration. Other damage results from landslides, tsunamis, or major fires which are started by the quake.

There are about a million quakes a year. However, not all of them are destructive. The intensity of an earthquake is measured on the Richter Scale, which begins at 0 and rises upward. The highest magnitude recorded to date is 8.9.

Major damage generally results from quakes that rate above 6.0. The exceptions are those whose epicenters lie far from inhabited areas. The actual cause of the quake itself is the rupturing or breaking of rocks at or below the earth’s surface. This breaking is produced by pressure which scientists believe may be due to a number of reasons, two of which are the expansion and contraction of the earth’s crust and continental drift.

In order to reduce the damage and to lessen some of the pain caused by earthquakes, scientists are working on ways to improve accurate prediction. Two kinds of instrument now in use for this purpose are seismograph and tiltmeter. The first records any shaking of the earth. Seismologists can accurately record the exact time, location and size of an earthquake. The second, as the name suggests, is used to record any changes in the tilt of the land.