Slide Scare Has Laguna Wondering: What Next? : Disaster: After facing fire and mud, residents have new worries about falling home values, cost of shoring up land.

It has been just over a year since Colleen and Steve Dunn scraped together enough money to buy a fixer-upper on a quiet cul-de-sac in the Temple Hills neighborhood, finally realizing their dream of living in this scenic artists’ colony.

Life has been anything but peaceful ever since.

In October, an ember from the wildfire that devastated parts of this community landed in the back yard of the Dunns’ Griffith Way home, bursting into flames and destroying their garden before firefighters extinguished it as it closed in on their home.

Two weeks later, a brief, pre-dawn rainstorm sent a torrent of water and mud from the newly scorched hillsides coursing through the Dunns’ neighborhood, two doors from their home.

And Tuesday, the couple attended a City Council meeting at which they learned their house may sit atop a previously unknown ancient landslide, news that prompted the city to hire geologists to investigate the stability of the 65-lot area where the Dunns live.

“It’s really been disheartening,” said Colleen Dunn, 35. “It’s just been one thing after another ever since we moved in.”

The residents of Laguna may not have seen the last of the financial and practical problems posed by hidden, prehistoric landslides beneath their homes, according to experts and maps maintained by the city and the state Division of Mines and Geology.

Landslides, ancient and otherwise, exist throughout Laguna, as they do across much of Southern California, especially its coastal communities, said Martin Short, professor emeritus of geology at Cal State Los Angeles and a top local authority on ancient landslides.

Short, who has dated several Orange County landslides at 15,000 to 20,000 years old, said problems often occur because much of the construction in Laguna and other slide-prone communities occurred 30 or more years ago, before most cities required geological evaluations.

“We create our own fate in a sense,” he said. “If we don’t have knowledge of the larger ancient slides and grade the land unknowingly, we can create a much worse situation where the slides are reactivated.”

In almost every case where an ancient slide begins to slip again, Short and other experts said, the culprit is water--often heavy rainfall, a broken water line or even over-watering of landscaping. The water reduces shear resistance along what geologists call the “slide plane,” an area typically made up of a soft, very plastic clay, allowing the mass of the old slide to break off and shift downhill.

In areas where development is minimal, geologists said they often can spot landslides from the surface. But the two slides now at issue in Laguna had escaped detection until recently, possibly because erosion and construction in the areas had masked their characteristic features: a bowl shape at the top, a gently sloping mid-section and a bulbous toe.

“I think we’re beginning to realize that these ancient landslides can be extremely subtle,” said Allen Bell, president of Petra Geotechnical of Costa Mesa, who has surveyed properties in both new slide areas. “We’re beginning to find out more about them and realizing that we need to do some deeper exploration in areas where we think they might exist.”

While the experts said almost any landslide theoretically can be stabilized, the costs of shoring up a very deep slide may be prohibitive. Various methods include supporting the slide with buttresses, using caissons and tie-backs to try to pin it in place or strengthening it with chemical injections.

Colleen Dunn said she and her husband, a graphic artist, are worried that if the Temple Hills slide is confirmed and includes their property, they and other individual homeowners might be required to bear the entire cost of stabilizing their sections of the hillside.

“We just don’t have the money to do that,” she said. “The things that concern us are the things that cost us.”

Of even greater concern, she said, is whether the talk of landslides may drive down their property’s value.

“We bought a house that needed a lot of repairs and we’ve been doing all this work in hopes of increasing its value,” said Dunn, who works as an actress. “That way, we figured if we had to sell, we would be able to make some money to live on for a while. But if it’s true that this is a landslide area, who’s going to pay top dollar for our house?”

Fears about property values are real for many residents, said Louise Turner, a longtime Laguna real estate broker.

“There are certainly lots of concerns out there about property values going down,” Turner said. “It would be very, very strange if there were not. The really sad thing is that people here, especially the ones in the fire areas, are so strung out already by everything that’s happened to them.”

But Jim Toohey, another broker with a long history in Laguna, said he has seen little so far to indicate real concern among his clients. Besides, he said, “I think once this thing has cleared and everything is properly investigated and all the reports are made public, the marketplace will move on.”

Laguna property values may well prove as resilient as those in Malibu and San Francisco, two other desirable California communities hard hit by natural disasters in recent years, Toohey said.

“I think we’re a lot like Malibu,” he said. “You know, rocks roll down onto the highway, then the whole place almost burns down and you still don’t see any shortage of people willing to pay anything to move in there.”

Word that geologists last week identified the suspected slide area in Temple Hills and confirmed that a second, previously unknown ancient landslide exists under part of nearby Mystic Hills sent a wave of concern across this community.

City officials and residents alike fretted about the cost, with some voicing concerns that the landslides, discovered during geological surveys in the aftermath of the fire, may ultimately prove more expensive than the fire itself.

For disaster-weary Laguna officials, last week’s decision to pay geologists $46,000 to study the Temple Hills area means the city has now set aside nearly $100,000 for geological investigations of the two neighborhoods.

Mayor Ann Christoph said the city might well end up spending more money to study and shore up its unstable hillsides than the $500,000 the city is now expected to pay as its share of the fire costs.

“It’s dismal,” Christoph said. “The whole thing is not what you want to be hearing at this point.”

Some said that merely including their properties in the Temple Hills study area, whatever the results, unfairly stigmatizes their neighborhoods, until now among the most desirable and valuable in Southern California.

At Tuesday’s City Council meeting, which resulted in a decision to inspect the Temple Hills area for an ancient slide, one Temple Hills resident complained bitterly that city officials had done enormous damage to numerous property owners in her neighborhood simply by releasing a map that shows the suspected slide area.

Others spoke privately of putting together a citizens’ group to sue the city in an attempt to force it to drop the Temple Hills investigation.

Still others tried to find humor in the situation.

Sheila Patterson, whose burned-out lot lies on the edge of the Temple Hills slide study area, said she and her neighbors have joked that even if they can rebuild, they may be forced to spend the rest of their lives living side-by-side, unable to sell their properties and unable to move.

“Before long, we’ll all be naming our children after each other,” Patterson joked. “We’ll be neighbors joined at the hip.”

* STOPGAP MEASURE: Laguna Beach officials are considering a construction moratorium for part of Mystic Hills. B1