The rift zones enable transport of lava tens of kilometers away from the caldera ( as seen in the current lower Puna eruption ) . They also serve as wedges , forcing the south flank of Kilauea downslope across a décollement – a nearly horizontal fault where the volcanic deposits rest on the oceanic crust – about 8 to 10 km deep . The combination of rifting and gravitationally driven slumping results in seaward movement of the entire south flank ( see image ) , especially around the Hilina Pali , with seaward motions of up to 10 centimeters ( ~ 4 inches ) per year
lower Puna eruption
2018 lower Puna eruption
Hilina Slump