The good earth not only sustains life; it is also the greatest killer. In some years the earth's paroxysms kill hundreds of thousands of people. For example, an earthquake in northern China on July 28, 1976, leveled the city of Tangshan. It killed more than 600,000 persons and injured an additional 700,000 [Associated Press, 1977].
We can only view with awe this and other natural catastrophes. Even though the toll may not be as high as in the Tangshan earthquake, death and destruction are common. Each year brings its own share of these natural disasters. Volcanic eruptions, hurricanes, floods, tornadoes, and tsunamis (water surges produced by submarine earthquakes) all kill, maim, and destroy. In most instances, timely warnings can and will reduce loss of life, but they seldom avert the destruction of property. A good example in recent memory is the havoc wrought by hurricane Agnes and its accompanying flash floods. In four days in June 1972 it killed 118 people and caused $3.5 billion in property damages, a record for losses of private and public property and facilities.