Graphic in Oct Geographical

[me]

This is a really good Graphic showing the Worlds largest caves (by volume) from the October Geographical. (not sure how long it will stay true.)



Geographical article

 

[andybrooks]

I'm not convinced that 676 km is 6.5 times the width of the English Channel.

 

[me]

I did wonder how accurate some of the numbers are but felt assured there will be someone on here who would correct it if needed

 

[Badlad]

I'm not convinced that 676 km is 6.5 times the width of the English Channel.

Looks pretty poorly researched to me. I'd have expected better of the RGS magazine. The two chambers seem about right though. The Miao room is the largest chamber according to the laser scanning project I was involved with. Not sure why they have included the second largest though.

The problem with identifying the largest caves by volume is that most have never been measured and those that have, have used very different methods likely to produce inconsistent results. There was an article in a recent Descent magazine which referenced a paper from the International Federation of Surveyors who published a figure of only 12.5M m3 after a laser survey of Hang Son Dong. 38.5M m3 is credited in the article to the commercial adventure company that run tours to the cave.

In the most recent Descent magazine there is a review of the new book on Lechuguilla Cave. In the review it lists a load of stats for the cave including a volume of over 61M m3. Clearwater cave in Mulu has also claimed to be the largest by volume. That used a mathematical approach designed by me back in 2009. It used available survey data, distance and LRUDs, to calculate volume from the elliptical truncated cones between each survey station. It was written up in an expedition journal back then, but as the length of the system has extended significantly over the last decade I'd estimate that it would now produce a volume of around 45M m3. However, none of these are using a comparable calculation and I doubt anyone is really that bothered either.

Even length is subjective as different survey teams do things differently. Do you include every alcove, aven and cross rift or do you just blast down the main routes? I have heard that up to a 25% difference in length can be achieved by different survey teams across the world's great systems. Luckily Mammoth is so far ahead it doesn't really matter.

Phew