A Wave in the Earth

As the great ice sheets of the last ice age melted and retreated, their weight was lifted from the underlying earth. This unloading and resulting crustal stress may have induced postglacial faulting and earthquakes. In his Perspective, Johnston discusses results reported in the same issue by Arvidsson ( p. 744 ), which indicate evidence of very large postglacial earthquakes along the Pärvie fault of northern Sweden.