Homeowners’ Patience Slips Away : Land Shifts: Driveways, curbs and pavement are cracking in a hillside neighborhood in Tarzana.

It’s not that Joe Zelman feels the earth move under his feet. But he does see the earth crack around his house, and he is not pleased.

Zelman, 70, is one of about 20 homeowners in a Tarzana hillside neighborhood where land has been shifting and sinking for at least 20 years. Recent letters and complaints by homeowners have intensified an investigation by Los Angeles city geologists and engineers.

City officials said they plan to meet with residents next week to assure them that the situation is being monitored. They said the situation does not seem to have worsened significantly in recent months.

But neighbors believe that the same phenomena that led to the sliding and collapse of two houses on the block 11 years ago may be happening again.

“We’re really scared,” said Zelman, who has lived for 16 years in the 4700 block of Conchita Way, the street where most of the problems exist. “We’ve heard that this is a disaster waiting to happen. The street keeps opening up.”

Geologists said the slippage is characteristic of unstable land on the north side of the Santa Monica Mountains.

“That whole region contains marine sediments such as sandstone or shale that are 15 million years old,” said Raymond Ingersoll, a UCLA geology professor. “The land is tilted northward and is generally prone to land sliding and unstable ground.”

Ingersoll said that when water from rain or irrigation gets into cracks, it lubricates the layers and weakens them. Cutting and grading the land further weakens it, he said.

“It’s a recurring problem that will always be there,” he said. “Each homeowner should get a good geological report before they buy a house up there.”

City officials said they are not certain about the precise cause of the shifting or what can be done about it.

“There does seem to be some kind of settlement, but we don’t know for sure,” said Jim Kaprielian, chief of the grading division for the city’s Building and Safety Department.

Geologist Mike Machalski, who is in charge of geological services for the city of Los Angeles, said the severity and depth of the instability has not been determined. “It seems to have been going on ever since houses were built up there,” he said.

He said city streets in the area have required frequent repairs.

Kaprielian said slope indicators had recently been put into the ground to determine the amount and direction of shifting. “It will be a while before we get any valid readings,” he said. “Only then can we find out what the appropriate action is.”

He added that some corrective filling was done on the land several years ago after the houses slid. “We have to determine whether the fill is consolidating or moving, which would mean that the problem was never really corrected,” he said.

Residents reported varying damage to their property. The porch, curb and driveway of Zelman’s home is lined with crooked cracks. “I’ve got it a little better than others, who have had to have their driveways redone,” he said. “We’re afraid a downpour will really do us in.”

The lot directly across the street is empty. Zelman said two houses across the street and above him slid off their foundations in a 1978 landslide and were destroyed.

Martin Bromberg, who lives across the street from Zelman, said the area’s reputation has made it difficult to sell his house. “I’ve had to knock off easily $100,000 from what it’s worth, and I still can’t get a buyer,” Bromberg said. He is trying to sell the house for $499,000.

“It’s terrible,” he said. “People are afraid to come up here.”

For the past several years, residents of the block have said the city has reinforced the land in areas and have put new concrete in spots. But those have been Band-Aid solutions, neighbors said.

“Patching it every 18 months is not going to do any good,” said Joel Palmer, whose Jacuzzi was cracked in the 1978 landslide. “Something more needs to be done, and the residents up here are as serious as a heart attack. They want to be sure that their homes don’t change ZIP codes come the rainy season.”