Bluebird canyon is known to have the worst Geology in Laguna. I am on bedrock with slight bedding angling to the south. My lot is very gently sloping and is among the very most stable lots in the town. The home I am building at the top of Portifino is on solid Brescia including a great deal of the "Blue Brescia" which is extemely hard. This is why it took months to excavate the site. Then we poured many deep caissons ....it ain't going nowhere!
Yesterday I drove up to a home under construction on Summit Way, that I designed.. This put me eye level with the slide and extremely close. I was able to analyze the movement of earth and have a pretty good idea of what happened.
The winter rains weakened the bond between the harder and softer layers of soil. The moisture adds cohesion , but as it starts to dry the cohesion is reduced and failure occured. It is similar to making sandcastles on the beach. When the sand is wet it sticks very well. As the sun dries the sandcastles they fail in shear along a weak plane.
Many of the residents and home owners blame the newer home for the slide. They say because it was not built well , it somehow created the slide. This is just not true! In fact , I am sure that the slide started above the home , at the visible shear plane in the photos. The newer home was in the path of tremendous earth movement , and failed and distorted under the force of land mass that was moving. The caisons helped the newer home to remain fixed to its bedding and it forced the moving soil mass around and to the right (as you look up the hill) of the home. This is evident, because there is a new slope where the land mass over lies the original grade ....maybe 10' high. I think the caissons of the newer home helped deflect the moving earth mass away from the home I remodled (Duka home) and added to many years ago. It lies behind the newer home and was protected.
When I remodled the Duka home , the geoogist and I added 12 caisons to stabilize the home. At the time Lonnie Duka really didn't want to spend the $60,000 for the caissons. This was about 1990. The other day he thanked me , and said tose caissons saved his home. It appears to be 100% in tact with not even a crack.
The most disturbing part for the local residents is the media. I have had so many phone calls I can't even start to tell you . They have invaded every hillside wit cameras and trucks....helicopters in te sky. Really probing questions ....trying to fabricate stories from threads of information...
Much of what is publishd is incorrect.
The home owners that lost their homes would naturally like to think it was someones fault.... a newer home, the City, anyone. I understand, and feel very sorry for them. The facts are the facts and the history shows a slide in 1978 , long before any new home was built...and many warnings about poor geology....it was well known among residents. Hopefully there are funds to rebuild their homesites and their homes.....In 1994 we had a huge fire here and the poorly designed original homes which had cedar shingle roofs and wood eaves were rebuilt with new and much better built, safer homes. In time, I think the same will occur here...