Much of what is known about the dynamics of active volcanos has been learned at Kilauea volcano. Deformation and seismicity data demonstrate that magmatic activity and slip on Kilauea's fault systems are coupled, yet the subsurface geometry of these faults and the deep structure of Kilauea's rift zones are poorly understood. The PI will analyze surface deformation data, including new GPS measurements, to elucidate the geometry of active rift and fault structures on Kilauea. Analysis of these unique data sets has the potential to answer fundamental questions concerning the dynamics of shield volcanos, and lead to an improved understanding of volcanic and earthquake hazards on Hawaii and elsewhere.