 A higher frequency of intrusive events along rift zones leads to elongated topographies of the affected edifices.Mathematical models show how the presence of rift zones contributes to a central horizontal bulge or ridge parallel to the orientation of the rifts.This same modelling shows how this central bulge is dependent on the ration between rift zone length and depth of the magma sources, with longer fissures over shallower sources being more positively associated with very elongated topographies of the associated flanks.