Lawrence Hargrave Drive-RMS animation

NSW Roads and Maritime Services have released an interesting video highlighting problems with the embankment in the northern amphitheatre between Clifton and Coalcliff. The cross section shown in the video is a little unrealistic but its useful in outlining aspects of the problem. The road here is constructed on talus below a buried cliff face in the Scarborough Sandstone. There's a bund here to protect the road from rocks and debris flows from the slope above that includes a steep slope in Stanwell Park Claystone and Bulgo Sandstone cliffs. The later not quite as high as those in the southern amphitheatre.

Link to video via this summary page HERE.

I had the pleasure of working on the bridge construction project back in 2003-2005. The budget at the time did not provide for a bridge over the northern amphitheatre.

Landslides from history: Coalcliff 1880s

Photos from the Wollongong Library archive showing landslides circa 1880s in the southern amphitheatre (embankment failure at top) and around the middle headland (slump in centre), between Coalcliff and Clifton (Google-bottom-southern amphitheatre in centre of photo, coke works at Coalcliff visible at top).
Note also the Hawkesbury Sandstone plateau visible at the LHS of the Google image.

This was called the Lower South Coast Road but was re-named Lawrence Hargrave Drive in 1947.
(DMR 22nd annual report)