Inskip 'sinkhole' was actually a landslide, experts say
THE science is out on what caused the sinkhole to form at Inskip Point campground, with academics and authorities presenting conflicting theories.
A Queensland Parks and Wildlife spokeswoman said the event was unlikely to be related to or caused by earthquake activity.
"Rather, it's most likely a natural phenomenon caused by the undermining of part of the shoreline by rapid tidal flow, waves and currents," she said.
"When this occurs below the waterline, the shoreline loses support and a section slides seaward, leaving a hole, the edges of which retrogress back towards the shore.''
However, University of the Sunshine Coast soil science and geology assistant lecturer Peter Davies observed that the first high tide to hit Inskip Point since the earthquakes off the Sunshine Coast in July-August coincided with the sinkhole appearing.
"The biggest tides happened over the weekend with the onset of the full moon," Mr Davies said.
He said the event had been inaccurately described as a sinkhole when it was more a landslide, and the liquefaction visible at the site could be akin to the process seen at events triggered by earthquakes, where buildings fall into soft, loose, wet dirt that was once firm.
The QPWS spokeswoman agreed, adding the technical term for the event was a "near-shore landslide".
Mr Davies and fellow USC professor Roy Sidle agreed that Inskip Point was an inherently unstable peninsula that was subject to continual natural processes of change.
"You get this meeting of all these different factors and they contribute to what you're seeing," Mr Davies said.