New research by Curtin University has revealed that underground cave systems beneath the Nullarbor Plain are considerably larger than previously understood, with evidence of hidden caves extending across the 500-kilometre stretch between Eucla in Western Australia and Ceduna in South Australia.

The research, conducted by Dr Matej Lipar, an adjunct research fellow at Curtin University's School of Earth and Planetary Sciences, used a new mapping technique to identify underground cave systems through features visible on the surface.

The study found that long trenches form when sections of underground caves gradually collapse, eventually reaching the surface. By examining these formations, researchers were able to identify the likely locations and extent of cave passages that remain buried.

According to Dr Lipar, where a surface trench ends, an underground cave may continue along the same line, allowing researchers to trace cave systems that would otherwise remain undetected.

Although the collapse process occurs extremely slowly over geological timescales, it is still taking place.

The findings also raise questions about the stability of sections of the Nullarbor, particularly where underground cavities remain close to the surface.

Dr Lipar explained that motorists travelling across the Nullarbor may unknowingly pass over cave systems located within approximately five metres of the ground surface.

He warned that sections which have not yet collapsed may present a greater risk because the underground cavities are not visible.

Dr Lipar has studied the Nullarbor for approximately 15 years and described its cave systems as important natural environments containing some of the world's most protected ecological sites.

The research provides a better understanding of the Nullarbor's underground geology and the processes that have shaped its extensive limestone landscape over millions of years.