14 December 2022
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:-
The Daily Breeze has a couple of images of the aftermath of the landslide, including this good image of the source area:-
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 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.