Update on San Pedro Ocean Cliff Landslide

I have posted several items relating to the on-going landslide on Paseo del Mar in San Pedro, including Dangerous Sink Hole Appears in San Pedro .

The folllowing is an update published in the Los Angeles Times:

A coastal bluff in San Pedro is slowly buckling and sliding toward the ocean, splitting open a coastal highway with sinkholes, cracks and deep crevices that are widening day by day.

Crews are hurrying to move sewer and water lines and utility poles and to reroute two major storm drains that join under Paseo Del Mar. Los Angeles city engineers have been monitoring the slide’s movement on the 100-foot-high bluff next to White Point Nature Preserve since cracks and fissures started to open up last spring.

Authorities indefinitely closed a 900-foot stretch of the highway between Weymouth and Western avenues inSeptember, putting up warning signs and barricades to keep out drivers and pedestrians.

Now, the highway and sidewalk have sunk more than a foot, opening deep crevices in the asphalt that cut a jagged diagonal line across the two-lane roadway. A wooden fence that once ran a straight line along the road now bends abruptly toward the ocean, a change that happened in just days. Cracks have also split open the earth in the adjacent nature preserve.

Work crews are keeping a watchful eye and taking daily measurements as the land creeps seaward. In the last week, the movement has accelerated to about half an inch per day.

Aerial view of landslide area before slippage began.

Contractors are working seven days a week, 10 hours a day, manning loaders and excavators that are carving new trenches to reroute two major storm drain pipes away from the moving earth. The project could take four more weeks, but the hope is to finish before any heavy rains, which could send storm water rushing into the area, rupture the pipe and further loosen the unstable slope.

City engineers, who have classified the slide as a coastal bluff failure, say it is far enough from a nearby neighborhood that no buildings are at risk of falling into the ocean.“If this fails,” said Hector Bordas, area engineer for the Los Angeles County Department of Public Works, “it means our pipe and storm drain system will also fail.”

A bluff-top breaking off into the ocean wouldn’t be unheard of on the south-facing side of the Palos Verdes Peninsula, where weak, slippery rock formations that dip toward the sea make the earth prone to landslides.

In 1929, a residential area two miles down the coast on Paseo Del Mar started sinking into the ocean, leaving behind a post-apocalyptic-looking bowl littered with chucks of concrete and asphalt that became known as the Sunken City. A chunk of the fenced-off parcel collapsed into the ocean in July 2010.

Starting in the 1950s, the Portuguese Bend landslide €” one of the most famous in California €” rearranged some 260 acres in Rancho Palos Verdes. And when the Ocean Trails Golf Course was under construction in 1999, a 16-acre section €” including the 18th hole €” slid dramatically into the ocean. In December 2009, a chunk of earth fell from a cliff in San Pedro less than a mile up the coast from today’s landslide.

Still, talk of another slide is enough of a curiosity that it draws a steady stream of visitors.