We plan on deploying nodes in ~150 locations across Mauna Loa and Kilauea Volcano on the Big Island of Hawaii. This deployment will consist of 3 linear dense arrays across the Kilauea East Rift Zone (KERZ) and Mauna Loa Northeast Rift Zone (MLNRZ). Our main goals are to understand (1) the fine structures of the Mauna Loa and Kilauea rift zones and the differences between the two, (2) the relation between the fine structures and their volcano-tectonic settings, as well as the frequency and intensity of rift zone eruptions, (3) the post eruption changes and constraints on rift zone healing and cooling of the magma plumbing system, and (4) the long-term evolution of the KERZ. Even though these are some of the most active volcanoes on Earth, there is little known about the fine-scale structure of the rift zones themselves.