An earthquake of magnitude 6.0 hit California’s Napa Vally in the middle of the night, leading Governor Jerry Brown to declare a state of emergency.
No deaths have been reported, but three people have been seriously injured, including a child in critical condition after they were crushed by a collapsing fireplace.
130 people have sought treatment for minor injuries.
The earthquake, which hit at 3.20am local time, has caused buildings to collapse, burst pipes, started fires and cracked roads.
The US Geological survey stated this was the most powerful earthquake in 25 years. They have warned residents that aftershocks of up to magnitude 5.0 are expected in the coming week.