Morning walkers discover ‘unusual’ sinkhole near famous Robe Obelisk

A sinkhole the size of half a tennis court has opened up at a popular coastal clifftop trail overnight.

A sinkhole the size of half a tennis court has opened up at on a coastal clifftop trail in the state’s South East overnight.

The collapse, near the Robe Obelisk, was discovered by a resident on their regular morning walk on Wednesday.

District Council of Robe chief executive James Holyman estimated the hole was “the size of quarter-to-half a tennis court”.

A sinkhole the size of half a tennis court has appeared on the, Robe coastline overnight. Picture: District Council of Robe

While sections of the limestone cliffs breaking off was a part of the natural erosion cycle, Mr Holyman said the location was usual.

It is not the first to form, with three smaller holes surrounding blow hole but he had not seen anything of this size before.

“The blow hole hasn’t blown for a number of years but the energy of the waves have eroded further in under and that’s where we’ve had this collapse,” he said.

“Having the ocean and limestone cliffs, we will have erosion and undercuts over time and they collapse every so often.

A sinkhole the size of half a tennis court has appeared on the, Robe coastline overnight. Picture: District Council of Robe

“This is an area that has been quite undercut and for it to fall a little bit inland, rather than directly on the coastline is a little unusual.”

Mr Holyman said permanent fencing would be installed as the council continues to monitor the coastline.

“To protect the community we’ve roped that off, and we’ll have a more detailed look at how deep that undercut is,” he said.

A new hole has formed on the Robe coastline overnight. Picture: District Council of Robe

“In the background you can see we’ve got our coastal trail, we believe that’s safe at the moment but we’ll do some more work.”

The council is working with Flinders University to gain a better understanding of the size and depth of undercuts in the limestone formations with a full review undertaken by a coastal engineer to ensure the protection of the coastline.