14 December 2022
Palos Verdes Estates: a coastal cliff landslide captured on video
Posted by Dave Petley
Palos Verdes Estates: a coastal cliff landslide captured on video
On Friday 9 December 2022 a landslide occurred on a coastal cliff at Palos Verdes Estates in California. Thanks to loyal readers Ernie Roumelis and Ken for highlighting this one – it is particularly interesting because it was caught on video from a helicopter. A Fox 11 helicopter was in the area, and succeeded in capturing the runout of the failure:-
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The Daily Breeze has a couple of images of the aftermath of the landslide, including this good image of the source area:-
The landslide at Palos Verdes Estates. Image by Chuck Bennett via The Daily Breeze.
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The image suggests that the failure was a structurally controlled wedge failure that turned into a dry debris avalanche. It is fortunate that the landslide occurred when the beach was largely unoccupied. Meanwhile CNN has a good image of the debris and the (fortunately unoccupied) pick-up truck that was struck by the landslide:-
The debris from the landslide at Palos Verdes Estates. Image by Beth Jay via CNN.
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The location of the landslide at Palos Verdes Estates is 33.804, -118.394. This is a section of coast, in common with many other locations in California, is no stranger to landslides. It is interesting that the event occurred in dry weather, ahead of the major rainstorm that affected this region over the weekend. Coastal cliff failures often seem to occur in dry weather (this is an area of active research across multiple groups at the moment). It should also be noted that artificial irrigation is common in this area, although I have no evidence of the likely cause in this case.
For those who are interested in the underlying geology, and the associated landslides, Ernie has highlighted a really interesting map produced by the California Geological Survey. Almost every cliff along this coast is likely to have experienced landslides of one form or another over time.
California remains remarkably prone to landslides of multiple types, both on the coast and inland, resulting from the combination of geology, climate, seismicity and the actions of people.
Dave Petley is the Vice-Chancellor of the University of Hull in the United Kingdom. His blog provides commentary and analysis of landslide events occurring worldwide, including the landslides themselves, latest research, and conferences and meetings.
Ah, we had often wondered, walking coastal paths (preferably during dry weather), whether we were safer than because land slides will occur more often after (heavy) rain. So no, that is not true. Good to know! Thank, you, Sara
The “sink hole” mentioned in the first video, and captured briefly in the aerial video at roughly 1:27 in the second video (well back from the active face, adjacent to the putting green) should be fairly concerning to the home owner above the cliff; most likely a retrogressive headwall fracture. They definitely should stop watering that lawn!
“Coastal cliff failures often seem to occur in dry weather (this is an area of active research across multiple groups at the moment). ”
Is there published data supporting this? I’d be interested in any references.