The new findings is reported by Brian Wernicke and colleagues from the California Institute of Technology (Caltech) and the Harvard-Smithsonian Center for Astrophysics in the current issue of Science . Since 1991 Wernicke and colleagues have been using the satellite-based Global Positioning System to measure the movement of Yucca Mountain with unprecedented precision. The team also used measurements made on a 14 km track across the proposed dump site by the US Geological Survey between 1983 and 1997. The researchers found that the south east region of the mountain had "moved significantly" to the south east at a rate of between 1 and 1.7 mm per year.

At first the researchers thought that an earthquake on the nearby Little Skull Mountain in 1992 could have caused the movement, but further calculations led them to conclude that Yucca Mountain itself suffers sharp periods of accumulated strain - in other words the region is in an period of increased earthquake and volcanic activity.

Although nuclear waste dumps are not currently designed to withstand earthquakes, Wernicke believes that increased tectonic activity should not prevent the storage of nuclear waste at Yucca Mountain providing that the activity is taken into account in the design.