Masonry arch systems and vaulted structures can reach a collapse condition because of actual displacements of their supports, induced by different causes, such as movements of underlying structures or subsidence of foundation systems. The paper presents a numerical tool for the computation of the displacements causing the collapse of elliptical arches subjected to dead loads, in the deformed configuration of the structure, following the gradual changes of the geometry. The analytical model is developed in the framework of the Limit Analysis, according to a kinematical approach, modelling masonry as a rigid in compression, no-tension material and avoiding the occurrence of sliding failures. A parametric survey is carried out to understand th...