Rancho Palos Verdes, a coastal community in the Los Angeles area, could be described as a geological ticking time bomb.
The affluent city sits atop steep cliffs overlooking the Pacific Ocean that, for hundreds of years, have been slowly shifting and giving way.
Now, that movement is accelerating. Whereas the ground slid downward 8 inches annually in years past, it has lurched 13 inches per week in some places between July and August.
The resulting landslides have ripped apart seaside mansions, buckled roads and forced utility provider Southern California Edison to cut electricity to nearly 250 homes to avoid the possibility of fires.
“Eight inches a year is measurable and they have had to do repairs to the road that crosses the area, but now it’s moving so rapidly that they’ve had to just close a number of roads, turn off the gas supply and cut electricity,” said Eric Fielding, a geophysicist at NASA’s Jet Propulsion Laboratory in Pasadena, California. “It’s crazy but you can’t keep re-installing electric wires every week.”
In Rancho Palos Verdes’ Portuguese Bend neighborhood, 140 homes will be without power indefinitely, while around 60 in the city’s Seaview section will be without service for a week or longer.
Gov. Gavin Newsom on Tuesday declared a state of emergency in the city.
The situation is the unfortunate culmination of intense rainfall over the past two years, experts say. The Palos Verdes Peninsula is composed of weak rocks and beds of clay that prevent water from draining properly belowground. So during periods of heavy rain or high tectonic activity, the bluffs can slip, turning constant, slow-moving landslides into catastrophes.
It’s not yet clear what, if anything, can be done to stop the land from moving.
“Basic physics says that once a body is in motion, it wants to stay in motion,” said Jonathan Godt, the landslides hazards program coordinator at the U.S. Geological Service.
The threat to Rancho Palos Verdes is not new. The land beneath the city has been moving for hundreds of years, scientists say, but it was mostly stable until a road construction project in the 1950s triggered the landslide to accelerate.
“The landslide was moving even faster in the 1950s than it is today,” Fielding said, “but they managed to stabilize it to a large extent by drilling wells and pumping out water.”
Now, heavy rains earlier this year and last year have caused the pace of the sliding to increase once again.
Fielding said it’s difficult to make a direct link between landslides and climate change, but rainfall is intensifying as a result of global warming because a warmer atmosphere can hold more moisture, raising the chance of severe storms.
Even with the knowledge that heavier rain is more likely, it’s challenging to forecast when major landslides will strike, Godt said. It can take months or even years after periods of heavy precipitation for the water to saturate deep rocks and clay and cause the land to deform.
It’s also difficult to predict which slow-moving landslides may become problematic. Landslides that move at a glacial pace over hundreds or thousands of years are not uncommon in Southern California — and around the world, Godt said.
“For many of those places, it’s not a problem over a human lifespan or even multiple human generations because that’s just a blink of an eye from a geologic perspective,” he said. “But, there are instances where a series of heavy rainfall events, or shaking from earthquakes, or other geologic processes going on beneath our feet get those landslides moving again.”
Rancho Palos Verdes is already facing setbacks to potential efforts to mitigate the land movement. Last month, the city said it had uncovered an even deeper landslide in the area that is also active. Officials said that movement, at a depth of more than 300 feet, is too fast and too far underground to dig drains and pumps to extract water.
Now that a state of emergency has been declared, Rancho Palos Verdes Mayor John Cruikshank said the money allocated will go toward helping the city government and landslide abatement efforts, but not to individual homeowners.
Homeowners whose power has been shut off will need to come up with tens of thousands of dollars or more to convert to off-grid alternatives, such as solar and battery technologies, Cruikshank told a local CBS affiliate on Wednesday. He hopes the state will help cover such costs.
Residents are already on the hook for damage to their homes, Cruikshank added, since typical home insurance policies don’t cover landslides, hundreds of which are documented in California each year.
Tim Kelly, a mechanical engineer who moved to the Portuguese Bend neighborhood of Rancho Palos Verdes 30 years ago, said he’s relying on his solar panels for power now, and remaining in his home. He attended a public meeting Tuesday in which residents pleaded with city officials for solutions.
“We’re resilient,” Kelly said of the community. “We’re not going anywhere.”
Kelly said that other homes in his area have shifted on their foundations, with some properties cracking and splitting in sections, but his house remains unmoved. He and his neighbors will not abandon their homes and expect government leaders and scientists to figure out how best to “stop the slide,” he added.
Kelly said that, for decades, the local government has failed to install long-term solutions to prevent water from saturating the canyon and divert it into the ocean. Now, the issue is coming to a head for the city and time is of the essence.
“The patient is sick,” Kelly said, “and something must be done to bring it back to life.”
This article was originally published on NBCNews.com
