How stable are caves over time?

[Simfish]

Especially over geologically significant intervals of time?

Is cave collapse inevitable?

 

[Evo]

Especially over geologically significant intervals of time?

Is cave collapse inevitable?

Since some of our oldest archaeolgical finds come from caves, I'd say that a lot are fairly sound. Of course there is no standard, it would vary from site to site.

 

[Studiot]

Well surely, as Evo says, it must depend upon conditions.

Once formed what is there to cause failure of a hole?
What actually sometimes fails is the material around the hole perhaps because of chemical degradation or Earth movement.
Sometimes the material does not fail, it is simply removed by an external agent such as the sea in the case of coastal caves, removing a whole cliff including a cave.
Sometimes the cave creating agent widens the cavern until it can no longer span the gap so the roof falls in. This happens in the case of acidic groundwaters waters in limestone regions.

go well

 

[Subductionzon]

On what sort of timescale? On an archeological timescale they are pretty stable. On a geologic one they aren't. They are a product of erosion, given enough time they are eroded away.

 

[Simfish]

Oh, good points. Hm, let's see - how long do most caves last, on average? I was mostly thinking geological timescales, in the millions of years.