Tag:natural=sinkhole

A  sinkhole, also known as a sink, shake hole, snake hole, swallow hole, swallet, doline, or cenote, is a natural depression or hole in the surface topography caused by the removal of soil or bedrock, often both, by water and/or by collapse of an underlying cavity. A typical form of a sinkhole is a crater. Sinkholes are abundant on  karst plateaus.

Don't mix this up with a  polje, which is much larger, or with a natural=cave_entrance. On the bottom of a sinkhole, however, there may be a cave entrance. In this case, you may wish to map both, if the sinkhole is of remarkable size; or the cave entrance only, otherwise.

Sinkholes vary in size from 1 to 600 m (3.3 to 2,000 ft) both in diameter and depth, and vary in form from soil-lined bowls to bedrock-edged chasms.

Consider also tagging any cliffs using natural=cliff

This tag can be specified using sinkhole=*, to precise the type of sinkhole; for OSM, used with anthropogenic=yes, natural=sinkhole and sinkhole=* can describe an anthropogenic sinkhole-like orifice, a cave-in for instance. Remember that natural=* doesn't necessarily designate natural features.

Photos

See also

• natural=cave_entrance – for the entrance to an underground cave, often found associated with sinkholes.
• natural=cliff – to map vertical or near-vertical rock faces, including the edges of some sinkholes.
• natural=blowhole – an opening to a sea cave which has grown landwards resulting in blasts of water from the opening due to the wave action.
• man_made=mineshaft – man-made vertical mine entrance
• inlet=bell_mouth – inlet that resembles a ponor sinkhole
• Proposed features/natural=cave – detailed mapping of caves