Glossary of Karst and Cave Terms
1. A process whereby a cavity or small conduit is developed in an unconsolidated soil due to progressive sediment removal by seepage water. The cavity develops headwards, as the fines are removed first and the coarser material is then washed out of the growing cavity . Definition 1 is often incorrectly applied to the formation of sinkhole development - the migration of smaller particles through openings created by larger particles is of no consequence in terms of sinkhole development and should not be confused as such. 2. Formation of a passage by water under pressure in the form of conduits through permeable materials when the hydraulic head exceeds a certain critical value . 3. The mechanical washout of caves in gravels, soils, loess, etc., and shows evidence of associated collapse.