Society has long felt the need for a means of predicting large earthquakes—to prevent loss of life and injury, to minimize damage and destruction and to lessen the terror associated with catastrophic shocks. This need is growing and will continue to grow as population expands and society and its systems for satisfying the wants of man become larger, more complex, and hence, more susceptible to major disaster.
Within recent years scientists in several countries, particularly Japan, the Soviet Union, and perhaps to a lesser extent, the United States, have increased their efforts to understand the earthquake mechanism with the goals of earthquake prediction and even earthquake prevention or control, among others. At present the situation is very promising. Very important advances in the understanding of the earthquake mechanism have clearly been made quite recently. Some predictions have even been attempted, not as yet with flawless success, but sufficiently good to be encouraging.