How to create a natural vacuum

[Liam A]

i work at a cavern attraction and one of the parts in the speech we say is that a section of the cavern was once filled with a naturally occurring vacuum until it was punctured and destroyed. we explain in the speech that the vacuum was created when a river packed in that area with mud and clay. we say there were pockets of water trapped inside, and since clay is much like salt in that obsorbs moisture, the clay took the water out and there was nothing to replace it and therefore a vacuum formed. a few things i would like to know is:
a: how accurate and plausible this is.
b: if it could be recreated artificially, by for example lining or partially filling a container or room with clay and filling it with water.
c: how long the process would normally take if it is possible
d: and what the effects the vacuum would have on certain materials, specifically metal, wood, rust, or mold

 

[Andy Resnick]

i work at a cavern attraction and one of the parts in the speech we say is that a section of the cavern was once filled with a naturally occurring vacuum until it was punctured and destroyed. we explain in the speech that the vacuum was created when a river packed in that area with mud and clay. we say there were pockets of water trapped inside, and since clay is much like salt in that obsorbs moisture, the clay took the water out and there was nothing to replace it and therefore a vacuum formed. a few things i would like to know is:
a: how accurate and plausible this is.
b: if it could be recreated artificially, by for example lining or partially filling a container or room with clay and filling it with water.
c: how long the process would normally take if it is possible
d: and what the effects the vacuum would have on certain materials, specifically metal, wood, rust, or mold

That makes no sense- as the water drained out, the space was filled with air- or some sort of gas. What is your evidence that the cavern pressure was below atmospheric pressure for any length of time?

 

[phinds]

I think if most of the water was absorbed into the clay with no way for air to get it (an unlikely premise but conceivable), this would not create a vacuum, it would simply create a chamber that was filled with water vapor instead of liquid water

 

[mfb]

The clay should have been moist all the time if it was in contact with water.

I can imagine that very weird circumstances with just the right timescales could lead to some amount of water in dry clay which then quickly gets shut off from the remaining water. But even then I don't think the vacuum would get very good. Maybe a slightly lower pressure.