Updated Laguna Slide Photos

[Mark Singer]

Again these were taken from my pool area . This time with a 500 mm lens and sun.

[Jeff Sudmeier]

Wow Mark, that will be quite the clean up effort!

[Kenneth Hertzog]

Mark
Just as long as the camera lens is getting stronger and your not getting closer
ken

[Mark Singer]

Good point!!!
Mark
Just as long as the camera lens is getting stronger and your not getting closer
ken

[Chris Padilla]

Mark,

What is wrong in the lower left picture (quadrant III for those mathematically-minded)? I can't make out if there is something wrong.

[Kent Parker]

WOW! Those poor folks. They lost their homes AND their property lines. That had to be a loud and horrible experience :(

Mark were you around to feel any vibration at your place? Here's hoping your on hard bedrock and not California sand.

Be well !

KP

[Vaughn McMillan]

Mark,

What is wrong in the lower left picture (quadrant III for those mathematically-minded)? I can't make out if there is something wrong.
Chris, I'm pretty certain that house used to be on the hill, not at the bottom of it. Mark can probably elaborate on it a bit more.

I'm glad to see Mark's house is still in the same lot it started in. My heart goes out to the folks who've lost everything, but like Mark, I wouldn't think of building (or buying) a hillside house that's not anchored to bedrock in one way or another. Then again, my dad is a geotechnical engineer, so I had this type of thinking drilled into me all my life. (I got sent to the Principal's office in first grade for correcting the teacher when she called the sidewalk "cement". By the age of six, I'd get beaten -- well, not really beaten -- if I called concrete "cement".) ;)

Thanks for the pics, Mark -

- Vaughn

[Ernie Nyvall]

Mark, glad that you are still on top the hill. It's got to be tough though watching that happen to you neighbors. Does your foundation check out thoroughly? Hope so.

Ernie

[Mark Singer]

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...