Comment: 07:45 - 09:24 (01:39)
Source: Annenberg/CPB Resources - Earth Revealed - 16. Mass Wasting
Keywords: "James Sadd", "Perry Ehlig", slump, "mass wasting", "Point Fermin", California, wave, erosion, "coastal bluff", slipping, over-steepening, speed, movement, block, landslide, "Coast Highway", "Paseo del Mar", beach
Our transcription: One of the most dramatic examples of slump can be found at Point Fermin, California.
Wave erosion here has cut away at the moist soft rock beds underlying the coastal bluffs, and this has created an oversteepened condition.
In this area dubbed the "sunken city" by residents, what began as a slump eventually led to a faster rate of slipping and much more extensive mass wasting activity.
Geologist Perry Ehlig has a long standing interest in the geologic history of Point Fermin.
This is the Point Fermin landslide.
It started moving in 1929.
It moved only a small amount, and people continued to live here, but then in 1940 it started moving very extensively, and as you can see here, it's broken into numerous small blocks.
In fact, most of the movement was in 1940 and then stopped, and then the area that we see over here that's all sunken has continued to move since that time.
Now this is the old road, the Coast Highway.
We're standing on Paseo del Mar right here, the remnants of it, and you can see the slabs out there that represent the offset portion of Paseo del Mar.
If somebody wanted to put enough money into it, they could remove and re-compact the slide material and found it on firm material below the beach level.
It might well be something that could be done economically if this were to be a hotel site or something like that.
Geology School Keywords