Napa Valley wineries reopening after earthquake

By Katia Hetter, CNNUpdated 26th August 2014
CNN's Kyung Lah reports on the impact of the 6.0-magnitude earthquake that struck Northern California on winemakers.
The strongest earthquake to hit California since 1989 jolted the state's wine country and caused a state of emergency.
Chad Myers explains how earthquake warning systems work, and why we can't predict seismic events earlier.