The SH impulse response of layered medium resulting from the application of a point source shear dislocation is studied by the generalized ray technique. Numerical seismograms of ground displacement in the range 10--100 km are constructed for a number of different crustal models and source descriptions. The results for shallow events show severe wave form modifications at epicentral distances as small as twice the source depth when models contain soft surface layers. A comparison of synthetic seismograms with observations from a central California earthquake of magnitude 4.6 indicates a moment of 2.1¿1022 ergs with a faulting duraction of 0.5 s. This moment is noticeably smaller than that estimated from the low-frequency level of the whole seismogram spectrum assuming the usual homogeneous half-space model. This occurs because the energy arriving with the surface waves and deep crustal reflections boosts the long-period portion of the spectrum, giving the impression of an anomalously large moment when calculated in the conventional manner. The close agreement between synthetic results and the actual data both in the time and in the Fourier transform domain suggests that our deterministic approach can be quite useful in understanding the complexity of seismograms recorded in the local field.