Just a case of stacking up enough concrete rings at the entrance....

We already use 2D passive seismic surveys at BGS to help identify subsurface features. These rely on natural background seismic noise rather than setting off explosions or using vibroseis trucks. It is good for the shallow subsurface, for example picking up buried glacial channels/valleys and...

In the same issues of Cave & Karst Science, there was an update on the caves and karst in the Chalk of the Eastbourne_Brighton area. https://bcra.org.uk/pub/candks/index.html?j=143. I suspect that there are new several entrances at the western end of Beachy Head Cave where the original survey...

Plenty of bird guano in Mulu (and bats). And they have a significant impact on cave development, as those who saw James (Max) Koether's BCRA talk back in January, and indeed my talk at Hidden Earth last year.

Most probably a crown hole over an old chalk mine, but as you have not provided any details of where it is, or size it is not possible to give an assessment of the hazard. I might add the risk depends on what you are doing; a small crown hole in an open field may be a low risk, but a major risk...

Scallop directions and other palaeoflow indicators such sediment ripple marks or cross bedding. Whether it is a phreatic or vadose passage, this could be marked on a cross section if you have a phreatic tube in the roof and a vadose trench below. Elevations and cross sections are essential if...

And mud... clay minerals washed in with the percolation water can impart various brown shades to the stal, more especially larger flowstones formed by larger drips, rather than straws.

And thanks to Jenny Potts at the British Caving Library for digging out some of the Chelsea SS records for this area. She dug out the relevant journals and set me scans quicker that it would have taken me to walk home and dig out my own copy! The BCL really is a fantastic resource and Jenny and...

There is considerable evidence of historic sand mining in the Godstone area, some of which are documented in the Chelsea Speleological Society records (these are not by the present collapse), but other unrecorded mines are likely to be present. The old six-inch topo maps do indicate the entrance...

Yes, almost certainly a burst water main flushing out the weak sands of the Folkestone Formation. The hearthstone mines are further north in the Upper Greensand. There have been a few instances recently of 'sinkholes' forming due to burst water mains or collapsing culverts. We had a burst water...

If there was a vacant position for Head of Armchair Pontification, I'm sure there would be lots of competition, and would lead quite a big team! I also use Lidar and coffee...

The radiocarbon dating of the human bones from Stoke Lane Slocker and Brownes' Hole were funded by the British Cave Research Association via the CSTRF Grant scheme, and the results published in Cave and Karst Science Vol 50(3), see Chamberlain and Mullan (2023), "Radiocarbon dates on human bone...

Alas, due to unforeseen circumstances, tonight's BCRA cave science webinar (Spyridoula Pappa. Palaeontological Perspectives on Caving in Thailand) has had to be postponed, and will be held next April The speakers for next year are as follows: 13th January: Max Koether 10th February: Jo De...

The next BCRA Cave Science webinar is this Monday 9th December at 7.30, where Spyridoula Pappa, Senior Curator of Fossil Mammals, Natural History Museum will be giving a talk on Palaeontological Perspectives on Caving in Thailand. For details of how to join, head over to...

I would be extremely wary of investigating any passages (assuming they were accessible) at the bottom of a deep shaft in unconsolidated weak sediment, especially one created by sediment being washed out by effluent from a leaking sewer... Imagine!! I suspect it got infilled pretty quick with...

Not inaccurate journalistic guff! See Waltham, T., 2008. Sinkhole hazard case histories in karst terrains. Quarterly Journal of Engineering Geology and Hydrogeology, 41(3), pp.291-300. "The void that the Guatemala sinkhole collapsed into was created by soil piping, whereby seepage water had...

There is almost certainly a fault trending NW-SE through the area, although the throw on it is probably quite small. I don't think there has been any fault movement since the caves were formed. The fault movements long predate the formation of the caves, with the last significant movement...

It is interesting to note that nearly all those sinkholes in the Guardian article are not natural karstic features, but mostly collapses over infrastructure (sewers, culverts), old mines or tunnels, the Merthyr collapse being one example. Only the Turkish ones are true karstic sinkholes, in that...

Might work in temperate areas, but in tropical caves, everything gets eaten and churned up, so all that remains are just insect wing carapaces (chitin), and even they get broken down.

Mixing dissolution is likely to occur, not so much in cave streams, but in porous rocks or in fractures. One example is in the Chalk or other porous limestones such as the Jurassic oolites where groundwater from different sources may meet along a certain horizon (eg sheet flint, marl seam...