(Photo: A landslide has caused a massive, approximately 200' x 240', sinkhole to open up and tear apart the pavement of Soledad Mountain Road, destroying two homes and forcing the evacuation of at least 100 others. Kent Horner/Getty Images.)
The landslide on Mount Soledad Mountain Road in La Jolla is an event geologists say is part of a continuing pattern over many decades or millions of years. KPBS Environmental Reporter Ed Joyce tells us the hillside has a history, a long history of activity.
San Diego City Geologist Rob Hawke describes the slide area this way.
Hawke: We've had past failures in the area. This one seems to be where we've got some geologic conditions that allowed a large block of land to slide off the side of the hill, much like a book off a tilting bookshelf.
Dr. Pat Abbott, emeritus professor of Geology from San Diego State University agrees. He says it's a bad area for homes.
Abbott: So you have a highly unstable situation here. Weak rocks, slanted up the same as the hillside with gravity pulling on them. There's no geologic surprises here. The only surprise is why would you build here to begin with.
The slide is in an area with a history of shifting land. In 1961 a landslide destroyed seven homes under constructioun. The slide area is about a half-mile north of where Frank Fraunces (fraun-sis) lives with his wife. He's lived in the Soledad Mountain Road home since 1994.
Fraunces: When we bought we had a geologist look at the place and we knew about the previous slides up the road.
The slide area is roughly the size of a football field. It’s been slowly slipping for years due to the natural instability of the soil. Fraunces says his property, while nearby, doesn't have the same history of slide activity. He feels his home is on more solid ground.
Emergency crews will be on the scene until geologists figure it out. Maurice Luque is with the San Diego Fire Rescue Department.
Luque: Well the process really falls into the realm of the geologist to determine how extensive this slide may be in the future if at all. They can't speak with certainty whether or not it's slipped all it's going to slip for the time being or whether their could be some additional slippage.
Ed Joyce, KPBS News.
