Geophysicists have been able to construct a moving image of a molten-rock-filled dike buried off the coast of Japan - a technique that could prove better than current methods for predicting volcanic eruptions. The experiment reported in the Oct 29 issue of the journal, Science, involved estimating the volume and flow of molten rock using data collected in 1997 by satellites and tilt meters installed to a monitor a seismically active area off the Izu peninsula southwest of Tokyo.