Strain accumulation in the Santa Barbara Channel: 1970–1988

Abstract

Geodetic observations between 1970 and 1988 indicate appreciable strain accumulation in the Santa Barbara Channel, California. Eleven line‐length changes from a six‐station geodetic network spanning the eastern two‐thirds of the channel were determined from electronic distance measurements in 1970/1971 and Global Positioning System observations in 1987/1988. Within this network the strains observed are spatially nonuniform. In the easternmost channel the strain is nearly uniaxial, with convergence of 6.4 ±0.9 mm/yr oriented N25°E ±5 °; this direction is consistent with the seismicity, which is dominated by thrust mechanisms with P axes directed to the northeast. In the central channel the strain is less well determined, but appears to include a significant component of shear that is left‐lateral when resolved on an east‐west plane.