Very-long-period (VLP) volcano seismicity often represents subsurface magma movement, and thus provides insight into magma system geometry and magma properties. We develop a fully automated signal processing workflow using wavelet transforms to detect and assess period, decay rate, and ground motions of resonant VLP signals. We then generate and analyze a catalog of VLP seismicity over the 2008-2018 open-vent summit eruptive episode at Kilauea Volcano, Hawaii USA. VLP seismicity occurred throughout this eruption that involved a persistent lava-lake, multiple intrusions and rift zone eruptions, and a climactic caldera collapse. We characterize trends in two dominant magma resonances: the fundamental eigenmode of the shallow magma system is a vertical oscillation of the magma column in the conduit and lava-lake, and higher frequency eigenmodes largely consist of lateral lava-lake sloshing. VLP seismicity was mainly triggered by lava-lake surface perturbations, and less commonly from depth. Variation in periods and quality factors occurred on timescales from hours to years. VLP seismicity exhibited varying correlations over time with other datasets such as ground tilt, SO2 emissions, and lava-lake elevation. Variation in VLP properties also occurred over days to months preceding and following intrusions and rift zone eruptions. Changes in VLP ground motions over various timescales indicate evolution of shallow magma system geometry, which contributed to the variation in resonance. However much of the variation on timescales less than months is likely from changing magma density and viscosity, reflecting a variable shallow magmatic outgassing and convective regime within the open conduit over the ten year eruption.