A cave-in is a collapse

Collapse

Collapse may refer to:* Collapse, the action a collapsible or telescoping object does* Collapse * Collapse * Collapse ** Cave-in is a kind of structural collapse** Collapse of the World Trade Center, a 2001 event...

 of a geologic formation, mine or structure which typically occurs during mining or tunneling. Geologic structures prone to cave-ins include alvar

Alvar

An alvar is a biological environment based on a limestone plain with thin or no soil and, as a result, sparse vegetation. It is also known as a pavement barren although this term is also used for similar landforms based on sandstone. In the United Kingdom the exposed landform is called a limestone...

, tsingy and other limestone formations, but can also include lava tube

Lava tube

Lava tubes are natural conduits through which lava travels beneath the surface of a lava flow, expelled by a volcano during an eruption. They can be actively draining lava from a source, or can be extinct, meaning the lava flow has ceased and the rock has cooled and left a long, cave-like...

s and a variety of other subsurface rock formations.

In mining, the term roof fall is used to refer to a range of collapses, ranging from the fall of a single flake of shale to collapses that form sink holes that reach to the surface. Note that roof falls in mining are not all accidental. In longwall mining

Longwall mining

Longwall mining is a form of underground coal mining where a long wall of coal is mined in a single slice . The longwall panel is typically 3–4 km long and 250–400 m wide....

 and retreat mining

Retreat mining

Retreat mining is a term used to reference the final phase of an underground mining technique known as room and pillar mining. This involves excavating a room or chamber while leaving behind pillars of material for support. This excavation is carried out in a pattern advancing away from the...

, miners systematically remove all support from under large areas of the mine roof, allowing it to settle just beyond the work area. The goal in such mining methods is not to prevent roof fall and the ensuing surface subsidence

Subsidence

Subsidence is the motion of a surface as it shifts downward relative to a datum such as sea-level. The opposite of subsidence is uplift, which results in an increase in elevation...

, but to control it.

Geological formations

• Alvar
  Alvar
  An alvar is a biological environment based on a limestone plain with thin or no soil and, as a result, sparse vegetation. It is also known as a pavement barren although this term is also used for similar landforms based on sandstone. In the United Kingdom the exposed landform is called a limestone...
  
   structures such as occur on the Stora Alvaret
  Stora Alvaret
  The Stora Alvaret is a limestone barren plain on the island of Öland, Sweden. Because of the thin soil mantle and high pH levels, a great assortment of vegetation is found including numerous rare species. Stora Alvaret has been designated as a World Heritage Site by UNESCO due to its...
  
  , Öland
  Öland
  ' is the second largest Swedish island and the smallest of the traditional provinces of Sweden. Öland has an area of 1,342 km² and is located in the Baltic Sea just off the coast of Småland. The island has 25,000 inhabitants, but during Swedish Midsummer it is visited by up to 500,000 people...
  
  , Sweden
  Sweden
  Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....
  
  
• Tsingy limestone such as occur in the Madagascar dry deciduous forests
  Madagascar dry deciduous forests
  The Madagascar dry deciduous forests represent a tropical dry forest ecoregion generally situated in the western part of Madagascar. The area has high numbers of endemic plant and animal species but has suffered large-scale clearance for agriculture...