At approximately 3:25 AM local time, a fairly significant earthquake hit Northern California. I had just woken up in Berkeley, and was annoyed that my neighbor’s large dog was barking when things started shaking. The epicenter of the quake, near Napa, California, is about 30 miles from me as the crow flies (see map below), so the effects were comparatively gentle here – a normal (for California) minor shaker. An Instagram User in Santa Rosa, about 15 miles from the epicenter, posted a video of his chandelier swaying, demonstrating the back-and-forth motion of the later moments of the quake.

But 6.0 on alluvial soil can lead to real damage. A look at the map showing the epicenter reveals that it is near the mouth of the Napa River, on what should be alluvial soil.

It appears be quite close to Napa Airport, in an area that has some commercial and industrial facilities. The City of Napa is nearby and is comparatively densely populated.

I wouldn’t expect any serious damage but at this hour we may be in for after shocks.

Update: there are television enws reports of a gas main on fire in downtown Napa, and fires burning in homes and trailer parks. Supermarkets near the epicenter are reportedly full of goods on the floors. Highway 29, the main highway going up the Napa Valley is reported closed. But fortunately, so far no reports of injuries, though the hour is still early.

Wineries may be impacted seriously. As wine is aged in barrels, they are stacked on racks, held in place by gravity. If there was serious lateral shaking, they could collapse.

The epicenter is also quite close to the Carneros region of Napa Valley, famous for Pinot Noir and other grapes.