This review is principally concerned with recent geodetic strain measurements in western United States undertaken by the US Geological Survey as part of the earthquake studies program and, as a consequence, is heavily biased toward the author's own publications. Most of the publications reporting crustal-strain measurements in western United States prior to about 1968 have been compiled in one volume (National Geodetic Survey 1973), and more recent work (with complete bibliographies) is summarized in three successive quadrennial reports to the International Union of Geodesy and Geophysics (Meade 1971, Savage 1975, Thatcher 1979b). The following conventions are employed in this paper: Strain, a dimensionless quantity, is reported in units of 106 Extension is taken as positive. To distinguish between engineering and tensor shear strain, we denote the former by γ and quote the units as μrad, whereas the latter is denoted by e and given the units of μstrain. Uncertainties in all cases are quoted as ± one standard deviation.
