Bubble-induced cave collapse.
Conventional wisdom among cave divers is that submerged caves in aquifers, such as in Florida or the Yucatan, are unstable due to their ever-growing size from limestone dissolution in water. Cave divers occasionally noted partial cave collapses occurring while they were in the cave, attributing this...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Public Library of Science (PLoS)
2015-01-01
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| Series: | PLoS ONE |
| Online Access: | http://europepmc.org/articles/PMC4388830?pdf=render |
| _version_ | 1818050455015522304 |
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| author | Lakshika Girihagama Doron Nof Cathrine Hancock |
| author_facet | Lakshika Girihagama Doron Nof Cathrine Hancock |
| author_sort | Lakshika Girihagama |
| collection | DOAJ |
| description | Conventional wisdom among cave divers is that submerged caves in aquifers, such as in Florida or the Yucatan, are unstable due to their ever-growing size from limestone dissolution in water. Cave divers occasionally noted partial cave collapses occurring while they were in the cave, attributing this to their unintentional (and frowned upon) physical contact with the cave walls or the aforementioned "natural" instability of the cave. Here, we suggest that these cave collapses do not necessarily result from cave instability or contacts with walls, but rather from divers bubbles rising to the ceiling and reducing the buoyancy acting on isolated ceiling rocks. Using familiar theories for the strength of flat and arched (un-cracked) beams, we first show that the flat ceiling of a submerged limestone cave can have a horizontal expanse of 63 meters. This is much broader than that of most submerged Florida caves (~ 10 m). Similarly, we show that an arched cave roof can have a still larger expanse of 240 meters, again implying that Florida caves are structurally stable. Using familiar bubble dynamics, fluid dynamics of bubble-induced flows, and accustomed diving practices, we show that a group of 1-3 divers submerged below a loosely connected ceiling rock will quickly trigger it to fall causing a "collapse". We then present a set of qualitative laboratory experiments illustrating such a collapse in a circular laboratory cave (i.e., a cave with a circular cross section), with concave and convex ceilings. In these experiments, a metal ball represented the rock (attached to the cave ceiling with a magnet), and the bubbles were produced using a syringe located at the cave floor. |
| first_indexed | 2024-12-10T10:53:44Z |
| format | Article |
| id | doaj.art-629908f796334d00b4becc53ffb40fc6 |
| institution | Directory Open Access Journal |
| issn | 1932-6203 |
| language | English |
| last_indexed | 2024-12-10T10:53:44Z |
| publishDate | 2015-01-01 |
| publisher | Public Library of Science (PLoS) |
| record_format | Article |
| series | PLoS ONE |
| spelling | doaj.art-629908f796334d00b4becc53ffb40fc62022-12-22T01:51:56ZengPublic Library of Science (PLoS)PLoS ONE1932-62032015-01-01104e012234910.1371/journal.pone.0122349Bubble-induced cave collapse.Lakshika GirihagamaDoron NofCathrine HancockConventional wisdom among cave divers is that submerged caves in aquifers, such as in Florida or the Yucatan, are unstable due to their ever-growing size from limestone dissolution in water. Cave divers occasionally noted partial cave collapses occurring while they were in the cave, attributing this to their unintentional (and frowned upon) physical contact with the cave walls or the aforementioned "natural" instability of the cave. Here, we suggest that these cave collapses do not necessarily result from cave instability or contacts with walls, but rather from divers bubbles rising to the ceiling and reducing the buoyancy acting on isolated ceiling rocks. Using familiar theories for the strength of flat and arched (un-cracked) beams, we first show that the flat ceiling of a submerged limestone cave can have a horizontal expanse of 63 meters. This is much broader than that of most submerged Florida caves (~ 10 m). Similarly, we show that an arched cave roof can have a still larger expanse of 240 meters, again implying that Florida caves are structurally stable. Using familiar bubble dynamics, fluid dynamics of bubble-induced flows, and accustomed diving practices, we show that a group of 1-3 divers submerged below a loosely connected ceiling rock will quickly trigger it to fall causing a "collapse". We then present a set of qualitative laboratory experiments illustrating such a collapse in a circular laboratory cave (i.e., a cave with a circular cross section), with concave and convex ceilings. In these experiments, a metal ball represented the rock (attached to the cave ceiling with a magnet), and the bubbles were produced using a syringe located at the cave floor.http://europepmc.org/articles/PMC4388830?pdf=render |
| spellingShingle | Lakshika Girihagama Doron Nof Cathrine Hancock Bubble-induced cave collapse. PLoS ONE |
| title | Bubble-induced cave collapse. |
| title_full | Bubble-induced cave collapse. |
| title_fullStr | Bubble-induced cave collapse. |
| title_full_unstemmed | Bubble-induced cave collapse. |
| title_short | Bubble-induced cave collapse. |
| title_sort | bubble induced cave collapse |
| url | http://europepmc.org/articles/PMC4388830?pdf=render |
| work_keys_str_mv | AT lakshikagirihagama bubbleinducedcavecollapse AT doronnof bubbleinducedcavecollapse AT cathrinehancock bubbleinducedcavecollapse |