Also, radar interferometry, the observational tool currently used, cannot "see" through vegetation, which may cover the side of a volcano. So for now, ground movement measurements are lost in those ecosystems. In order to improve their observations, Zebker and Paul Segal, also of Stanford University, proposed launching something like an array of dedicated satellites, with specific observational capabilities that could document movement more often and at smaller scales¿and even monitor only certain types of materials.
Researchers still do not fully understand the reasons behind the changing flow of magma in and out of magma chambers, causing volcanoes to go up and down, or to erupt. "We're not very good at predicting what it is yet," Zebker says, "and that's the focus of the research: to better characterize the processes so we can try and identify what¿s happening at any given time."