Scientists have been trying to understand how Earth processes occur and influence each other, and are now looking at advanced, next-generation observation technologies. The third International Workshop on the Scientific Use of Submarine Cables and Related Technologies (SSC'03) was held last June at the University of Tokyo to review what has been achieved and to explore future observations technologies. Scientists and engineers started looking at opportunities to conduct observations that would cover the dynamics and structure of the Earth's interior, plate dynamics, natural resources, geohazardous events such as earthquakes and tsunamis, hydrogeological processes in sediment, heat and material exchanges or circulation through the ocean, dynamics of microbiological or ecological processes, deep water currents, physical oceanography, marine meteorology, and air-ocean interactions, etc., from the deep earth to its surface. Cross-disciplinary areas might develop depending on the scales of observations of spatial coverage. Long-term and real-time observatories would surely deepen our knowledge of these processes, about which much is still unknown. We believe that the workshop will lead to the initiation of new steps toward future sea floor observation technologies and scientific findings.