Abstract: A single-end-mount seismic isolator for protecting a structure from the effects of seismic shock or other external applied forces includes a load shaft that is secured at its first end to a mounting surface on which the structure is supported. So secured, the load shaft projects beyond a base of the structure, on which an actuator is supported. A resilient element, such as a friction spring, is operably interposed between the load shaft and the actuator to allow relative motion between the structure and the mounting surface in the event of a seismic shock or other external applied force. The resilient element also absorbs energy of such motion. The single-end-mount design facilitates seismic retrofitting of existing structures and servicing of seismic isolators in the field. In dual-action embodiments, the resilient element includes primary and secondary resilient elements for damping in two directions.