Satellite techniques for the study of secular variations in position

Some crustal motions which are precursory to earthquakes are discussed and a system for monitoring such motions is proposed. Studies have shown that the scale of a dilatant region is an indicator both of the magnitude of subsequent earthquake and of the time interval between the earthquake and the precursory phenomena. Monitoring may be accomplished by the use of corner reflectors at sites situated in an array over a given region, such as California, for example, the sites being tracked by means of a laser system operating in the Geopause satellite.