Geologists Get 3-D Pictures Of Beach Erosion On California Coast

FORT FUNSTON (KPIX 5) -- The sound of the Pacific surf pounding the coast of California is rhythmic, hypnotic -- and one of several causes of a problem as constant as the waves: erosion.

"The problem is, we don't have good measurements," says Jonathan Warrick, a research geologist with the USGS.

He's been studying the effects of erosion on the 160 foot cliffs around Fort Funston, but getting good scientific measurements is tricky.

"It's always been difficult to measure cliffs, especially. Think about trying to get out there with survey rod. Of course, we wouldn't do that, it's too dangerous," he says.

That's where the California Coastal Records Project comes in. Kenneth and Gabrielle
Adelman have been taking aerial photos of the coastline for years.

They took their photos with lots of so-called 'overlap,' taken one, after another, after another.

For example, two photos taken in 2004 show the same geographical markers. When combined using photogrammetry, the USGS can build a 3-D model and get erosion measurements they otherwise couldn't.

There's plenty of anecdotal evidence of erosion at Fort Funston, but, now the USGS has actual numbers to match with the scenery.

The measurements are critical for understanding both the current rates of erosion, and projecting for the future.