[Basilar membrane nonlinearity]

The nonlinear correction of the cochlear partitions movement equation becomes the main part in the resonant section. In the neighbourhood of this section the periodic solution, having the drawing force frequency omega, gets the region of the non-stability in the interval (see abstract), where a is the vibration amplitude and h is the basilar membrane thickness. The amplitude jump in the unstable region may be a stimulus exciting the hair cells and also the cause of cochlear eddies phenomenon.