Scott and Robin Spivey had a sinking feeling that something was wrong with their home when cracks began snaking across their walls in March. The cracks soon turned into gaping fractures, and within two weeks their 600-square-foot garage broke from the house and the entire property—manicured lawn and all—dropped 10 feet below the street. It wasn’t long before the houses on both sides collapsed as the ground gave way in the Spivey’s neighborhood in Lake County, about 100 miles north of San Francisco. … Unlike sinkholes of Florida that can gobble homes in an instant, this collapse in hilly volcanic...
