THE Earth’s crust may be all that is supporting the world’s tallest
mountains. A study of earthquakes by a geophysicist in Britain has revealed that
the upper layer of the Earth’s mantle, which underlies the continents, may be
too weak to do the job.
Geologists cannot examine subsurface rocks directly, but they can map the
strongest layers by tracing earthquakes, which occur only in strong, brittle
rock. Previous studies have suggested that continents are held up by two strong
layers, the upper crust and the upper mantle, separated by a weak quake-free
layer in the lower crust.
However, Keith Priestley…
