Frequent occupation of a network of instrument and target sites using an Electronic Distance Meter (EDM) over 21 months has led to the recognition of two distinct patterns of ground deformation. Corrected slant distances to reflector targets involve either continuous shortening or an oscillatory pattern of shortening and recovery. These two patterns are considered to reflect the response of the volcanic edifice at near-field and far-field positions, respectively. At near-field locations non-elastic deformation is predominant over elastic deformation and rebound associated with changes in the magma conduit pressure are not detectable. At far-field locations elastic deformation is dominant allowing recognition of relaxation in the conduit magma pressure. Recognition of the two patterns assists monitoring of crater stability and may aid long-range forecasting of future activity at the volcano. ¿ 1998 American Geophysical Union