InSAR measurements at Spurr cover two seismic swarms. The first swarm took place in 1996 – 1998 at Strandline Lake, 30 km northeast of Spurr. Initial InSAR observations showed no evidence of strong surface deformation, ruling out magma intrusion at depths <10 km (Kilgore et al., 2011). Later observations by Lu and Dzurisin (2014) identify broad inflation associated with this event, and find that best-fitting models agree with a deep source (12-16 km). InSAR measurements covering a second earthquake swarm in 2004 – 2005 beneath the summit of Spurr also show broad inflation at 10 – 14 km depth. Modelled volume changes associated with both events are similar (0.04 – 0.06 km³), and are interpreted to be caused by episodic intrusion of magma into the crust. InSAR measurements outside of these periods show no evidence of deformation.