When a naturally occurring material is broken down by processes of weathering and erosion.
Seismic uplift is the vertical movement of the Earth's surface caused by the upward displacement of subsurface rocks in response to tectonic forces or the release of stress along a fault. It can lead to the formation of fault scarps, ridges, or other landforms and can also contribute to the development of earthquakes in certain areas.
Sieving is an adequate method.