Ping!
Many of these homes should have never been built. It's sad for the owners, but JMJ, the danger is known when building takes place on landfills and on stilts along canyon sides.
Our house before this one, was built on a canyon side overlooking what was once the San Diego River. I was glad when we sold it. Every earthquake had me running out the door.
Just down my street, there's a newly constructed condo thang of maybe 5 units and as a little girl we used to play in that small canyon, and, over the years I have watched that canyon get filled with trash, dirt and a variety of weeds and small tree limbs. I was stunned when construction commenced and even stopped by to show the owner/builder what it looked like 40 years ago, and he didn't give a rip. I had black and white photos in my hand which showed the adjacent houses... yet, the city gave him a permit to build on that landfilled lot.