In a model for the depth distribution of deep earthquakes, I assume that deep earthquakes occur only above a critical deviatoric stress and that where the stress is achieved the seismicity rate is proportional to the strain rate. The model seismicity rate increases sharply before terminating, in agreement with the observed depth distribution. Since the assumption are valid for most plausible seismic process, no large stresses or unusual earthquake mechanisms near the termination of seismicity are required. ¿American Geophysical Union 1991