What to know about the landslide threatening homes in Southern California's scenic Rancho Palos Verdes

A landslide in the Southern California city of Rancho Palos Verdes has been wreaking havoc in the scenic oceanfront community for more than seven decades, according to city records.

On Tuesday, California Gov. Gavin Newsom declared a state of emergency for the city after the local utility provider shut off electricity and gas to 245 homes due to broken pipes and power lines causing hazards.

The governor said in a proclamation that the city is located on four out of five sub-slides that comprise the Greater Portuguese Landslide Complex. He said land movement in parts of the complex has "significantly accelerated following severe storms in 2023 and 2024."

But problems caused by the slipping land are nothing new for the city, which has spent millions of dollars on numerous engineering reports and fixes since the 1950s to stabilize the ground and prevent homes from crumbling, according to city records.

“Stopping the largest landslide has been a top priority for the city of Rancho Palos Verdes. City officials have allocated over $4 million to the stabilization of this natural disaster," reads a city report reviewed by ABC News from the 1980s.

In 1990, a city report found the landslide complex was moving less than one foot per year. A city geologist survey in June of 2024 concluded that some parts of the landslide complex have been moving 9 to 12 inches per week.

The latest report released by the city this week blamed the recent acceleration in the movement of the land on heavy rains in 2022 and 2023.

"The current rainfall total is 23.19 inches, approximately 170% of the season average over the past 67 years," according to the city report.

Meanwhile, the growing landslide zone has spread about 680 acres, prompting evacuation warnings.

"The City has been navigating this crisis for almost two years, and the skyrocketing costs of responding to this emergency are taking a toll on our coffers," Rancho Palos Verdes City Manager Ara Mihranian said in a statement this week. “For months, we have been asking for public assistance from every level of government."

Mihranian said Newsom's state of emergency declaration will bring much-needed financial assistance for the city to respond to recent power shutoffs "that are upending our residents’ lives."

But Mihranian said the declaration "does not open up individual financial assistance to affected residents."

"The City continues to strongly call on Gov. Newsom and the California Office of Emergency Services [Cal OES] to ask President Joe Biden to declare a federal disaster in the City, which would trigger the deployment of Federal Emergency Management Agency (FEMA) resources and potentially individual assistance," Mihranian said.

The earliest city report on the landslide dates back to April 25, 1957, when the ground movement extended over 200 acres.

"The most rapidly moving portion of the slide has traveled about 22 feet in the seven months between Sept. 17, 1956, and the date of this report," reads the 1957 report.

Over the decades the city has gone to extreme lengths to slow the landslide down. One of the earliest measures taken was inserting a series of 20-foot-long, 4-foot diameter reinforced concrete pins near the bottom of the landslide area in an attempt to slow down the moving land. The city has also installed dewatering wells to remove groundwater, according to reports.

But one city report from the 1980s said the earth was moving at more than an inch per day and that "140 homes had been destroyed or displaced" and "10 million tons of mud and rock have been deposited in the ocean along several miles of coastline."

In 1987, the city was forced to relocate Palos Verdes Drive South, a main artery in the city, due to the damage from the landslide, according to a report.

In the 1980s, homeowners also took drastic measures to save their residences. Historical photos included in city reports show homes lifted and placed on adjustable steel beams.

"To maintain a habitable environment, these residents must perform maintenance frequently on the foundation of their homes," a report from the 1980s said. "It is necessary to level the foundation since the earth has been moving more than one inch per day. Foundations have to be specially constructed so that the structural integrity of the house can be maintained."

Now, homeowners like 81-year-old Sallie Reeves are taking similar steps to save their houses.

Reeves gave ABC News a tour of her home of four decades, pointing out cracks in her walls, collapsed ceilings and a widening fissure running the length of her master bedroom, rendering it uninhabitable.

Reeves said she is working with a contractor on plans to lift her home and build a steel foundation that will sit on cribbing, repairs she expects will be out-of-pocket expenses.

"This has been a hard pill to swallow," Reeves said.