Microearthquakes reveal the kinematics of the Bárðarbunga caldera ring fault; both during the 2014-2015 volcanic rifting event and gradual caldera collapse, and its subsequent, ongoing re-inflation. Manual analysis of earthquake phase arrivals has been used to produce reliable hypocenter locations with tightly constrained focal mechanisms for events both during and after the eruption. Phase arrival polarities are reversed between events that occurred during the caldera collapse and those that have occurred since. Both precise relative relocations of the seismicity and focal mechanism solutions confirm that this is due to slip reversal on the same ring fault structure. The fault planes are steeply dipping (averaging 78 ± 6°). Furthermore, the spatial distribution of aftershocks following large-magnitude post-eruptive events provides constraints on the shape and size of the fault plane and the amount of slip that typically occurs in caldera events.