There is evidence from multiple methods that the western flank of Arenal is subsiding steadily at a rate of up to 10 cm/yr. Arenal stopped erupting in 2010 after almost 42 years of lava effusion, mostly on the volcano’s western side. Deformation is centred on these recent deposits. Measurements of subsidence at Arenal have been made for several decades, including dry tilt meter (1986-2000, Mora et al., 2013), Electronic Distance Meter (Avard et al., 2012) campaign GPS (Muller et al., in revision) and InSAR (2005-2010, Ebmeier et al., 2010). Long wavelength near-vertical subsidence (2-5 km diameter) has been attributed to elastic loading, consolidation of erupted material and basement subsidence. Higher rate deformation above elevations of ~800 m has a greater component of westward motion and is thought to be caused by multiple shallow, sliding units.