Imagine for a moment that the mountains you see around the San Fernando Valley are taller—much taller. Actually, those mountains were much taller, but millions of years of torrential rains and flooding washed silt, sand, and gravel down their slopes to the bottom of the mountains. Over millennia, this erosion gradually raised the Valley's floor with alluvium while lowering the height of the area’s mountains.
The geology of Woodland Hills can be placed in three classifications (Geological Survey of California, n.d.):
* Upper Miocene marine, found in the foothills of the Santa Monica Mountains
* Alluvium, found on the floor of the San Fernando Valley
* Upper Pliocene marine, found on the northern half of Chalk Hill north of the Ventura Freeway
These sections provide information about earthquakes, landslides, and flooding that affect Woodland Hills.
Alluvium. (n.d.). In Wikipedia. Retrieved from https://en.wikipedia.org/wiki/Alluvium
Miocene. (n.d.). In Wikipedia. Retrieved from https://en.wikipedia.org/wiki/Miocene
Melinkoff, E. (1987, March 26). Savvy Gardeners Can Wring Pleasure From Valley's Clay. Los Angeles Times. (Nancy Harrington quotation). Retrieved from http://articles.latimes.com/1987-03-26/news/vw-464_1_gardening-classes
Pliocene. (n.d.). In Wikipedia. Retrieved from https://en.wikipedia.org/wiki/Pliocene
Sources used for Figures
Figure 1. Geology of Woodland Hills
Geological Survey of California. (n.d.). Geologic Atlas of California-Los Angeles Sheet. Retrieved from http://www.quake.ca.gov/gmaps/GAM/losangeles/losangeles.html#