The 1983 landslide at Malibu's Big Rock Mesa, which spawned more than 200 lawsuits against Los Angeles County, is still moving at its northern limits and along the top of a bluff overlooking Pacific Coast Highway, according to a geologist's report commissioned by the county.
About 90 homes and businesses in the two danger areas and on the south side of the highway at Big Rock Beach are still "at risk," the report states. Any slide that rains dirt and boulders onto the beachfront homes also would probably block the highway, the only direct link between Malibu and the west Los Angeles area.
A system to drain underground water has stopped the movement of the main slide mass. But all of the approximately 230 homes on the mesa will probably continue to be plagued by cracking walls and splitting floors "over the next several months or few years" as the land resettles, the report says. Pavement, utility lines and even the equipment that is in place to remove the water could also be damaged by the settling of the slide, the report says.
The main slide mass has not yet reached the level of stability required by the county for new construction; more movement could be triggered by tremors or earthquakes, the report says.
To make the entire mesa stable again, it may be necessary to raze nine of the expensive homes there, improve surface drainage, install a public sewer system and inject grout into the earth, the report says. It does not address the questions of how much such repairs would cost and who would pay for them.
County officials have not resolved a dispute over how much money is due Laguna Hills geologist Dennis A. Evans for the study and so have not received the report, which is dated March 15, 1986. "We cannot comment until we've read it and given it an in-house review," said Roslyn Robson, a spokeswoman for the county Department of Public Works. The county has written Evans a letter demanding the report, Robson said.
Evans said he also will not comment on the report until the county gets it and makes it public.
At least two attorneys obtained the report by subpoena and some homeowners also have copies of parts of it.
Last fall, a judge ruled that the county should pay $2 million to a couple whose home was destroyed by the movement of hundreds of thousands of cubic yards of earth under the surface in the fall of 1983.
Because of the landslide, which involves about 220 acres, 28 homes on the sea cliff have been condemned by the county as unsafe. Nearly all of the rest were damaged in the 1983 movement. Values of Big Rock homes plunged afterward.
The county approved development on the mesa with an inadequate drainage system rather than requiring sewers and "must now bear the loss when damage occurs," Los Angeles Superior Court Judge Jack T. Ryburn said. The decision was hailed as a test case by attorneys for more than 200 other Big Rock homeowners who had filed similar suits.
The case is on appeal and no decision is expected before late fall. The county is also pressing forward with countersuits against the property owners, contending that the residents are responsible for the slide because they stopped operating a private drainage system there.
If all of the Big Rock property owners win their suits, the cost to the taxpayers could range from $200 million to $500 million.
Big Rock residents and their lawyers said they were not surprised to learn that parts of the slide are still moving. Continuing fractures and fissures in the homes there had already convinced them.
"Homes that had been repaired within the last year have shown renewed damage," said Richard Norton, an attorney who represents about 50 Big Rock families. "One case where people had tried to save the home from destruction has now turned out to be futile."
Kenneth Chiate, an attorney for about 160 families who filed suit, said one of his clients got a letter from the county just two weeks ago that warned the family against sleeping on the uphill side of the house because of unstable ground.
The upper limit of the slide, called the headscarp, and the bluff "have been problems from Day 1. We knew that," said Margaret Richards, president of Concerned Citizens for Water Control, a committee of Big Rock residents.
"But I'm glad that basically the hill itself will settle down and stabilize," she added. "I'm quite confident that we will eventually achieve the element of safety that is required so we can stay here and breathe a sigh of relief."
Still, the severity of the suggested repair measures, especially the destruction of nine homes in the headscarp area, caught residents and attorneys off guard.
Evans wrote in the report that "repair of the headscarp area may not, in a practical sense, be possible."
The best way to stabilize the headscarp, he wrote, would be to remove the homes at its base, take out the earth there and reconstruct it with fill that is compacted or chemically treated so it will harden.