An inertial sensor includes a proof mass spaced apart from a surface of a substrate. The proof mass has a first section and a second section, where the first section has a first mass that is greater than a second mass of the second section. An anchor is coupled to the surface of the substrate and a spring system is interconnected between the anchor and the first and second sections of the proof mass. The spring system enables translational motion of the first and second sections of the proof mass in response to linear acceleration forces imposed on the inertial sensor in any of three orthogonal directions.