Gargantuan sinkhole surprises farm worker at sunrise in New Zealand


#1

Originally published at: https://boingboing.net/2018/05/07/gargantuan-sinkhole-surprises.html


#2

Is this where the Kaiju are going to attack from?


#3

I’m so glad to live in a country where the bedrock is nearly uniformly granite.


#4

Eh, I’ve seen bigger in Minecraft.


#5

How many times did he ride across it on his motorcycle when it was just about to go…?

I wonder if ground penetrating radar could be mounted on a drone to cheaply fly a survey grid over a property, checking for hidden sinkholes?

Low power, moving and not being in contact with the ground would limit its sensitivity and penetration, but it’s a big target to look for.

Ha!

While ground penetrating radar is great for archaeology and people searching for hoards buried in the middle of farmland, the biggest application is safety. You need only to Google “Florida sinkhole” to see the value of peering into the Earth.


#6

According to Scott, the sinkhole could have been forming for up to 100 years, after decades of rainfall slowly eroded the farm’s limestone rock foundations.

What makes this sinkhole so much bigger than ones that have preceded it in New Zealand is the record-breaking rainfall that helped cause it – almost 170mm of rain in 38 hours.

Umm, I don’t think the recent rainfall made this sinkhole so large, I think it was the 100 years of erosion that volcanologist Brad Scott talked about.


#7

Rainfall eroding limestone foundations under the earth over a mere century? Ha. No.
I’m looking at a limestone church that is almost 200 years old right now, and while it has been refaced a few times, it has not “eroded away” despite it’s direct exposure to regular storms and other atmospheric effects.

I’ll bet this was fracking or some such shite.


#8

If this guy comes out’a that hole, you’ve hit gold Mister!

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#9

Why is it Fissure shaped? All the sinkholes I’ve seen have been roundish.


#10

As a non-hydrologist by profession or avocation, my guess would be that it was caused by underground flowing water rather than extraction of groundwater.


#11

Just out of interest when did the non British English speaking world decide a floor in a building was a story and not a storey? Seems endemic these days. Personally I think many of these “sinkhole N storeys deep” tales are just tall stories.


#12

Tenuously related :slight_smile: :slight_smile:

Well played :smiley:


#13

cut limestone in contact with the water table, even just the damp table, in acid soil or acidic groundwater conditions will degrade much faster than limestone just exposed to some rain.


#14

mumble mumble geology something or other


#15

Look up “Karst”

Dissolution of limestone (and dolomite) by moderately acidic rainwater and ground water forms enormous caves, gorges, and tunnels all over the world. But you are right to say its not on a centuries timescale.

Not sure why they’d be asking a vulcanologist about ground water, limestone, and sinkholes as none of those have anything to do with volcanoes - but maybe they used the term rather than all-purpose geologist, or maybe he reached back to his undergrad classes to remember these facts


#16

This doesn’t appear to be in limestone. Looks more like beds of sand, silt, and the odd volcanic ash here and there. Sinkholes can form in non-karst settings as well. It just takes material that can be mobilized or dissolved by ground water and somewhere for it to go.


#17

Because it happened in a place called ‘Earthquake Flat’! Water erodes fastest along the path of least resistance - I’m guessing this is a faultline; thus it’s fissure-y.

I’m generalizing from the short article, but hey - I do like to play in the dirt and bang rocks together.


#18

I’ve been to Rotorua, and it’s the most beautiful place you’ll ever go that smells a wee bit like an egg salad sandwich fart.

Not really too surprised at this though, there’s so much volcanic/hydrothermal activity in that area.


#19

The Victorians believed that the sublime was the penultimate in the appreciation of beauty. The example I heard was that the Swiss mountains are pretty, but seeing the Swiss mountains while being scared shitless riding downhill fast in a runaway carriage is sublime. The terror heightens your senses and makes you more aware of the beauty of nature.

I propose that the slightly Hellish whiff of egg salad sandwich fart was heightening your impression of its beauty.

…on the other hand, Denver smells the same way on Ozone Alert Days.


#20

Why do these accounts always give heights in “stories” and lengths in “football fields” instead of just feet or meters? I always have to first recall how long a football field is, etc. Part of the dumbing-down of America.