allikiviidid

Allikiviidid refers to a phenomenon observed in certain geological and hydrological contexts, particularly in areas with karst topography or permeable bedrock. It describes the visual appearance of pebbles or small stones that seem to "dance" or move slightly within the water of a spring or seep. This movement is not due to the stones themselves having intrinsic motility, but rather the result of the water flow.

The effect is caused by the underlying aquifer's pressure pushing water upwards through fissures and porous materials. Where this water emerges at the surface, it creates a gentle, localized bubbling or effervescence. These small bubbles, as they rise through the water and around the submerged stones, create currents that lift and nudge the pebbles. This continuous, albeit subtle, disturbance gives the impression that the stones are actively moving on their own.

Allikiviidid is often associated with the freshness and purity of spring water, as it indicates active groundwater circulation. The clarity of the water in these locations further enhances the visibility of the effect. While the term itself might be informal or regional, the underlying physical process is well-understood in hydrogeology as a manifestation of artesian pressure or significant groundwater outflow. It is a natural visual indicator of subterranean water movement reaching the surface.