Tuesday, January 01, 2013

Thornton Beach

San Francisco's Ocean Beach transitions southward into progressively higher bluffs in the vicinity of Fort Funston, which then continue to rise on into Daly City towards Mussel Rock.  About a mile of the bluffs between Fort Funston and the northern portion of Daly City are marked by a spectacular deep-seated landslide complex - characterized by rolling topography and shore-parallel ridges and swales.

My brief research suggests a range of ages for this slide - which is often the case with these features - since some people are referring to the age of the overall feature, whereas others refer to specific events or even to more recent reactivation.  From what I can tell, the landslide dates back hundreds of years, but experienced significant movement in the 1906 earthquake and continued to experience some additional sliding during the past century.  Regardless, the railroad, and later the highway, that was built on the face of the bluffs from San Francisco to Pacifica (and beyond), in the early 1900s, has not survived - except in small pieces and on interpretive signs.

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