Los Angeles gained fame in the 20th century as the ever expanding city. You could get a canned laugh on early TV just by showing some outlandish location - an ice floe, a tropical beach - posted with an L.A. City Limit sign.
Everyone knew that Los Angeles was the town that always grew.
Not so well known (and no laughing matter) is the shrinking of Los Angeles. That was not a part of the Chamber of Commerce's sunny narrative.
Coastal Los Angeles County began dropping into the Pacific at the end of the last Ice Age, as rising sea levels ate away at what had been inland hillsides and are now coastal bluffs. The movement accelerated after beachfront development in the 1920s.
In 1929, a six-acre crescent of San Pedro near Point Fermin began to sag into the bay. The slippage of the bluff was so gradual that nearly all the affected homes were moved off their migrating lots, leaving behind a jumble of tilted roads and building foundations. They have continued south into the Pacific ever since as the eerily named Sunken City.
In the fall of 1969, a 300-foot-long crevice opened up at edge of the slide area and more cracks appeared two streets away. In the summer of 2010, a big chunk of Sunken City dropped 100 feet into the surf. And in early November this year, new movement of San Pedro's slow-motion landslide prompted city officials to declare the site "an immediate and life-threatening hazard." (Los Angeles Times, 11/15/11)
A 900-foot section of Paseo Del Mar was blocked off to keep out the curious. Power lines were cut. City crews began relocating water and sewer lines to the stable side of the bluff.
Stable for now. The lesson from still-sliding Portuguese Bend is that earth movement along vulnerable parts of the coast is inevitable, even if it takes generations. The Portuguese Bend slide began in the early 1950s when residential development destabilized almost 300 acres of hillside and arroyos on the Palos Verdes Peninsula. Some homes were lost; others were saved.
But movement continues, worsened by seasons of heavy rain and the unpredictable effects of development outside the slide area. State and county engineers have spent 60 years mapping Portuguese Bend, probing its geology, and applying various strategies - from "dewatering" wells to "slide dams" - to keep the land where we prefer it to be. But all of that is only temporary.
Paul Simon had it right; in L.A. we're "slip slidin' away." But slowly. Very, very slowly.
[Update: The heavy rains on 11/19 and 11/20 sent another block of the San Pedro slide area into the sea, prompting new concerns about how much of Los Angeles is fated to become part of the Sunken City]