San Pedro landslide called ‘life-threatening hazard’

A slow-moving landslide on a coastal bluff in San Pedro is worsening, exposing huge, deepening crevices along a seafront roadway and dropping chunks of earth and concrete into the ocean below.

The slide is serious enough now that city crews have begun building a fence around the crumbling 100-foot bluff in an effort to keep onlookers from getting dangerously close to the mass of land sliding toward the sea.

City workers, who have been scrambling to clear the slide area of vulnerable infrastructure, broke ground Friday on the 8-foot chain-link fence. The move came a day after various city and county agencies met at L.A. City Hall to discuss their response to the landslide.

In a report, city officials called the landslide “an immediate and life-threatening hazard” to those who enter the area. The LAPD is boosting patrols to monitor the closed-off site for trespassers and vandals.

The city also plans to commission a geological study to determine the extent of the bluff failure, identify weak and susceptible rock and test the stability of surrounding land, Mayor Antonio Villaraigosa’s office said.

City engineers have been tracking the land’s movement near White Point Nature Preserve since cracks appeared last spring.

Though the city says the slide is far enough from a nearby neighborhood that no buildings are at risk, it did close a 900-foot stretch of Paseo del Mar in September. Workers erected warning signs and barricades on the two-lane road to keep out drivers and pedestrians.

The warnings, apparently, have not been enough.

Workers have arrived to the slide site on weekend mornings to find dog walkers and other visitors who have sneaked in or jumped the construction fence to take a peek.

“I don’t think everybody understands how dangerous it is in here,” said Hector Bordas, area engineer for the L.A. County Department of Public Works, which has contractors working seven days a week to re-route two storm drains from under the sinking roadway.

In recent weeks the shifting earth has opened up gaping roadside fissures. On the bluff slope, chunks of earth have broken away and slid into the ocean, turning the water a murky brown.

The asphalt itself is a wreck of jagged pieces that sink into an abrupt depression about 6-feet deep, swallowing up fence posts and revealing a twist of underground pipes and tree roots. On Monday, segments of concrete storm drain pipe were lapped by the surf after plunging to the base of the bluff. A retaining wall that once helped support the road had split open.

In addition to the new fence, workers have put up pole-mounted floodlights and will be placing more signs around the blocked-off area “to warn of the potential for catastrophe,” according to a city report.

City and county crews have for weeks been hustling to relocate sewer pipes, water lines and other infrastructure beneath the sinking roadway.

Electricity has been cut to overhead power lines that run along Paseo del Mar and before long, the utility poles that hold them will be moved out of the way too.

The Palos Verdes Peninsula coast has long been prone to landslides because of slippery rock formations that dip toward the sea.

When ocean waves wear away at the base of coastal bluffs, the instability can cause spectacular landslides like the one at Portuguese Bend in the 1950s, which rearranged some 260 acres in Rancho Palos Verdes, or the 1999 landslide that sent 16 acres of the Ocean Trails Golf Course into the ocean.

tony.barboza@latimes.com