California homes are falling between the cracks-literally.

About 100 miles north of San Francisco in a neighborhood called Lakeport, cracks in the ground that have turned into cavernous divides are splitting homes, causing them to break and sink beneath the ground.

The community was built upon now-dormant volcano Mount Konocti; officials can't say whether or not the volcano is a contributing factor in the strange splitting occurrence.

"We have a dormant volcano, and I'm certain a lot of things that happen here (in Lake County) are as a result of that, but we don't know about that," county public works director Scott De Leon told Yahoo News.

Residents Scott and Robin Spivey noticed cracks in the walls of their Tudor-style home that widened by the day.

"We want to know what is going on here," Spivey said.

Spivey, former city building inspector, and his wife were among the eight households that have now been evacuated in the Clear Lake area of Lake County. 10 more are on imminent evacuation notice.

"It's a slow-motion disaster," Randall Fitzgerald, Lakeside Heights resident, said.

These kinds of collapses that happen in volcanic areas with steep hills can move numerous feet one day, and a quarter of an inch the next.

Some, including Consultant Tom Ruppenthal of Utility Services Associates in Seattle say that groundwater is partly to blame. Water has surfaced in the area-there has suddenly been a wellspring of water at the top of hills, where not much groundwater runs-that erodes some of the land until it splits.

"It's very common for groundwater to shift its course," he said. "I think the groundwater has shifted."

Until homeowners can settle finances with insurance companies-some of whom have left residents high and dry, as these kinds of home emergencies are not often covered-they will have to make due.

"It's a tragedy, really," contractor Dean Pick said while taking pictures in Lakeport for an insurance company. "I've never seen anything like it."