An analytical investigation in a vertical fluid saturated porous layer distant from the axis of rotation is presented when vibration occurs in the presence of a stable temperature gradient. A linear stability analysis is used to determine the convection threshold in terms of the critical Rayleigh number for variation within the porous layer and for the offset distance from the axis of rotation. The results indicate that the presence of vibration in a stable system serves to reduce the Rayleigh numbers (both within the porous layer and due to offset from the axis of rotation), thus destabilizing the system when a stabilizing temperature gradient exists. (C) 2018 Published by Elsevier Ltd.