Friday, May 16, 2014

Winnipeg "Sinkhole" Earns Fame

The beautiful city of Winnipeg.  Click for photo credit.
Winnipeg, in the Canadian Provence of Manitoba, is underlain by an ancient paleokarst landscape.  The soluble rocks are covered by a blanket of glacial till and lacustrine clay.  Caves are present at some depth and sinkholes do occasionally form.

One sinkhole has been making all the news in Manitoba--and it has its own Twitter account.

This is the famous St. Mary's Road sinkhole that opened Wednesday.  However, it isn't your normal sinkhole.  This one seems to have formed after a broken storm water drain pipe broke and washed out sediment underlying the roadway.

Sinkholes form naturally after the collapse of a natural void space underground.  These voids typically form in soluble bedrock like limestone.  You probably have been in one of these voids such as Carlsbad Caverns or Mammoth Cave.  Sinkholes are very common in places like Kentucky, Florida, and the Yucatan Peninsula of Mexico.

However, the St. Mary's Road "sinkhole" isn't a natural sinkhole at all.  It is a human-made phenomena brought about through the failure of aging subsurface  pipes.  There are lots of examples of these types of "sinkholes" all over the world.  We just had one not too long ago down the road from me in Brooklyn that almost ate a van.

Geologists cringe when people call these kinds of phenomena sinkholes because we all use the term for the naturally occurring sinkholes that form in karst landscapes (landscapes of soluble rocks).

Yet, the term is so widely used for depressions that form from failed pipes that it is time to approve of the term sinkhole for these kinds of phenomena.  I think the geologists in the room will understand that they are not the natural ones.

Plus, these types of sinkholes are the Kardashians of the geologic world.  Everyone talks about them even though they might not have much substance.

What other geologic phenomenon has its own Twitter account?

You can follow the Winnipeg sinkhole at @Wpg_sinkhole

A big thanks to CBC Radio in Winnipeg for having me on the air this morning to talk about the sinkhole and sinkholes in general.

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