Here's the evacuation map.[1] The location in Google Earth.[2]
This isn't where you'd expect trouble. About 2km, and west of the Pacific Coast Highway, there are houses on the top of the seashore cliffs. They're not the ones in trouble. This slippage has reached a kilometer inland and is taking out a subdivision that did not seem to be under threat.
I think this begs the much larger question of when should taxpayers have to pay for mistakes made by builders, homeowners, (in this case) soil engineers, etc.? I'm somewhat familiar with this area. This slide has been known about for decades, but people kept buying and building because I'm sure in many cases soil engineers evaluated the situation and said that it would be possible to mitigate the amount of slide. Now we know they were wrong (some of those opinions were likely very recent because, before last winter, the movement was nowhere near as pronounced (heavy rains over the winter accelerated what's happening, as I understand it)).
In this case, the "logical" finger could be pointed at the soil engineers. So then the homeowners sue the engineers? But of course once the engineer is insolvent, then what? Does the government step in? Once the government says "you're licensed" to an engineer is the individual homeowner really supposed to be on the hook for these types of mistakes if they hired an engineer to sign off? And what of the government, which, locally, at least, is typically made up of residents who will gain or lose depending on how these situations are evaluated?
And then the broader issue is how do we handle these situations for much larger cases such as floods in Florida, or wildfires in California? Cases where people thought it was acceptable (not prudent) to build, and where the government gave the green light to do just that.
It doesn't seem like there are easy answers, but the idea that houses are destroyed or at the least unlivable and then John Q. Taxpayer keeps bailing them out seems untenable both financially and politically, though that's exactly what keeps on happening in many of these cases.
My take is that this is all coming to a head because of how frequently it's happening (I won't label it broadly as "climate change" to keep from inflaming opinions). But it seems like there needs to are some national plan that says "we'll bail you out once, but after that it's private insurance and if you can't get that you're on your own." And I'm only saying that in cases where some authority (engineer, government planning dept., etc.) signed off in the first place. If you were reckless enough to build without any of that then you should obviously be on the hook from the start.
This area has been seismically active for a long time. Just a matter of time before an event like this happens. The homes sit above a nature preserve that was never developed because of the land movement. The Portuguese Bend is a road that needs constant repairs. Some people just dared to live on top of it.
I used to mountain bike that preserve, but many of the trails closed from the slides. It may someday become an even bigger preserve now.
These arnt related to seismicity. This is dirt moving via loading and rain fall lubricating a natural slip plan. And has been moving for many decades. Typically to keep these things together they need very deep pylons and tiebacks and the rest, but it's unlikely developers want to spend more than needed on things no buyer sees.
The image in the article of the very nice and expensive looking homes right along the coastal cliffs, built directly atop obviously risky ground, is essentially a visual study in irrational optimism.
This isn't where you'd expect trouble. About 2km, and west of the Pacific Coast Highway, there are houses on the top of the seashore cliffs. They're not the ones in trouble. This slippage has reached a kilometer inland and is taking out a subdivision that did not seem to be under threat.
[1] https://www.rpvca.gov/1707/Land-Movement-Updates?os=ios&ref=...
[2] https://earth.google.com/web/search/Rancho+Palos+Verdes+Beac...