[imatfaal (OP)]

An enormous hole opened in the ground in a housing estate in Germany - officials are looking into it!  What causes something like this?  Nobody was hurt but a hole this size 40x20x15 metres could have caused huge problems.

Huge German Hole

By the time the officials decide what caused it the press will have lost interest and I will not remember to check up on the local news - thus the question here.

[CanopicJar]

Many times it is caused from a cracked Storm sewer or sanitary sewer line...

[JimBob]

There are many things - what the Egyptology mentioned, karsted limestone as the bedrock, e.g. But invariably the ultimate cause is water flowing for a long time removing the soil.

[imatfaal (OP)]

Is the material at the bottom of the hole liquid?  One of the other videos on the beeb (hole in texas) and at the bottom of the hole was a strange grey fluid, I wasnt sure if it was mud or water or strange fluid earth (this was whilst it was still collapsing

[Geezer]

Maybe somebody forgot to jiggle the handle on the toilet? Personally, I think it was more likely caused by the very rare Eweropean mole "Molusgermanicus Giganticus".

[maffsolo]

Some sink holes are caused by a reduction of the water table in some areas.
Some area ground surfaces depends on this subterranean hydraulic pressure.
Places in Florida, if you dig down about 10 feet, you will have water flooding the hole.
-----------
SINKHOLES and the AQUIFER
 
 Sinkholes originate beneath the surface when groundwater moves through the
 limestone and erodes large voids, or cavities, in the bedrock.
 When water fills a cavity, it supports the walls and ceiling,
 but if the water-table drops, the limestone cavity is exposed to further
 erosional processes that eventually result in the collapse of the cavity,
 causing a surface indenture, or sinkhole. The sinkhole becomes
 a primary site of recharge, where surface water can enter the aquifer
 and replenish the groundwater supply.
-----------

 [ Invalid Attachment ]

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Or  'Der Riesen- maulwurf

   

[JimBob]

See? Water moving in a limestone Karst -- You doubted my word? 

 [:0]  [] [:0]  [] [:0]  [B)]

[maffsolo]

I just seen the News on the Weather Channel, follow up.  Scientist suspect a rock formation moved.
That was it, nothing that was not all they said...

[Bass]

Maybe somebody forgot to jiggle the handle on the toilet? Personally, I think it was more likely caused by the very rare Eweropean mole "Molusgermanicus Giganticus".

Nessie's cousin??

[JimBob]

I just seen the News on the Weather Channel, follow up.  Scientist suspect a rock formation moved.
That was it, nothing that was not all they said...

Did a limestone aquifer collapse - or something similar?

[maffsolo]

I just seen the News on the Weather Channel, follow up.  Scientist suspect a rock formation moved.
That was it, nothing that was not all they said...

Did a limestone aquifer collapse - or something similar?

The report I seen on TWC was not very specific, they limited there report to the phrase "Rock formation collapse".

Sorry JimBob, that was the only News on that incident I seen and it was a fluke that I seen it.  []

Seems that no one wants to publicly commit to any specifics, until they investigate the hole.

Although, according to the internet, they will definitely express how they will fill it.

I wonder if they will fill it with limestone?

http://www.minnpost.com/scientificagenda/2010/11/03/23001/humongous_sinkhole_opens_up_in_germany

[imatfaal (OP)]

The damned press love reporting the disaster - but it is near impossible to find any form of follow up; which was why I asked on the forums.  It would be nice, if a little utopian, if several months down the line the beeb would add a link to the article which explained the reasons behind the occurrence.  But whilst I was looking at the recent German sinkhole, I looked at previous articles that the beeb automatically found, of a chinese and texan sinkhole; and neither of those had any follow up. 

I had assumed that they were genteel and localised earth movements - but water erosion and subsequent collapse makes perfect sense now it has been explained.  Thanks for all the info.