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Although it sounds like a Batman punch, this EarthWord is closer to the Bat than you’d think...

EarthWords is an on-going series in which we shed some light on the complicated, often difficult-to-pronounce language of science. Think of us as your terminology tour-guides, and meet us back here every week for a new word!

Image: Water Droplet in a Cave
Water at work in a karst environment creates cave formations like these. Credit: Alex Demas, USGS. Public domain

The EarthWord: Karst


  • Despite sounding like a Batman punch, karst actually refers to a type of landscape where the underlying rock formations are partially eroded by water. Usually, these areas are made up of limestone or marble.

  • The most famous aspect of karst landscapes is caves, which predominantly form when groundwater dissolves limestone and erodes open spaces in the rock.


  • Karst is the German name for a limestone region around the Italian city of Trieste.

Use/Significance in the Earth Science Community:

  • Karst landscapes make up a large part of the United States, and because of their ability to hold water, are often home to significant sources of groundwater.

  • Karst landscapes are also home, as mentioned, to the vast majority of the world’s caves, which themselves are unique ecosystems with important species.

  • Finally, because they’re susceptible to erosion beneath the surface, karst landscapes are also at risk for sinkholes, which can range from small to large enough to swallow entire buildings.


  • USGS studies the groundwater aspect of karst in its Office of Groundwater, tracking groundwater quality, quantity, and movement.

  • On the cave side of things, USGS studies bats, aquatic insects, and other ecosystem aspects of cave ecology.

  • And, last but not least, USGS studies sinkhole hazards, including what causes them and what areas are susceptible.

Next EarthWord: This EarthWord sounds like some flu meds, but it’s closer to runny rivers than runny noses...

Hungry for some science, but you don’t have time for a full-course research plate? Then check out USGS Science Snippets, our snack-sized science series that focuses on the fun, weird, and fascinating stories of USGS science.