A magnitude 6 earthquake jolted both sides of the California-Nevada border, tossed boulders onto a major roadway and was felt as far off as Las Vegas and even San Francisco, with days of aftershocks predicted, authorities said. The quake shortly before 4 p.m. Thursday was centered south of Lake Tahoe near Walker, eastern Sierra Nevada. No major damage or injuries were reported, AP quoted authorities as saying. It was followed by dozens of aftershocks, including at least a half-dozen of magnitude 4 or above, according to the U.S. Geological Survey.