Kılauea Volcano, the most persistently active basaltic volcano on Earth, has long served as the premier natural laboratory for investigating magma generation, transport, and storage in basaltic systems.  For 37 days in 2023, we conducted a hybrid seismic experiment at the summit of Kılauea volcano, Hawaii, that combined more than 1,800 three-component nodal seismometers with 396 controlled vibroseis sources, yielding over 15 million P- and S-wave arrivals. Travel-time tomography produces sub-kilometer-resolution

three-dimensional models of Vp, Vs, and Vp/Vs within the upper 3-4 km beneath the summit.  We use that result to constrain an inversion of 720 gravity disturbance observations to infer subsurface distributions of density and shear modulus. The models define two principal

magma storage regions beneath Halema‘uma‘u (HMM) and the south caldera (SC), and moreover suggest that the HMM is the principal reservoir supplying magma to conduits to the southwest and east rift zones.