An alternative to the method of Langston (1982) for determining fault-plane solutions from a single 3-component seismic station is proposed. The method calculates synthetic P and SH seismograms for three basic orientations of a shear dislocation embedded in a plane layered Earth model, and uses least-squares to minimise the error between the observed data and a linear sum of the synthetic seismograms. The result is five trigonometric functions of fault strike &thgr;, fault dip Δ, and rake of the slip vector &lgr;. When applied to the Borrego Mountain event of 9 April 1968, the method provides a solution which is in close agreement with well-constrained studies of the main shock.