Interesting archive from the city:
Mike Cooper, Rancho Palos Verdes, stated that he was a third generation grading contractor; expressed his belief there were two main factors that had created the Palos Verdes landslides: the first factor was the subsurface geology, which consisted of volcanic and sedimentary rock dipping toward the ocean at roughly the same angle as the average slope of the land surface; that on top of the sedimentary rock there was a heavy clay layer called bentonite, which created a slide plane when wet that caused land movement; and that the only thing that prevented an ancient landslide from moving was the amount of friction between the land mass and the bentonite layer. He noted that in 1956, this friction balance was altered when Los Angeles County road crews placed 350,000 cubic yards of fill on the upper slope of the slide mass, which started the land movement and created a downhill domino effect, causing the entire land mass to begin sliding towards the ocean with a year’s time.
Get ready to slide folks below the new TANGERINE ROAD ...
