  This paper presents science potential of a deep ocean antineutrino
observatory under development at Hawaii. The observatory design allows for
relocation from one site to another. Positioning the observatory some 60 km
distant from a nuclear reactor complex enables precision measurement of
neutrino mixing parameters, leading to a determination of neutrino mass
hierarchy. At a mid-Pacific location the observatory measures the flux and
ratio of uranium and thorium decay neutrinos from earth's mantle and performs a
sensitive search for a hypothetical natural fission reactor in earth's core. A
subsequent deployment at another mid-ocean location would test lateral
heterogeneity of uranium and thorium in earth's mantle.
