What sort of distance does the ground move?
A The surface of the Earth is in constant motion as a result of weather systems acting on the oceans and solid crust, and due to quarry blasts and traffic noise in urban areas. On rural sites, these microseismic displacements are typically only a few microns (thousandths of a millimetre), while the waves from large, distant earthquakes might move the ground tens or hundreds of microns.
