I’ve noticed two quakes since I moved to California in 2008. One of them was small and brief: it felt like when you’re on the highway and a larger vehicle goes by quickly, so that the wind of its passing makes your car sway momentarily to the side.

The other was last night.

I was trying to fall asleep when it hit. Took me a second or two to figure out that yes, this really was an earthquake. Then it kept going, while my husband woke up and we stared at one another, trying to figure out if we ought to run for a doorway or something. It was strong enough to worry me, not strong enough to be really scary: 6.1, with an epicenter near Napa, maybe fifty-five miles from here. For the people there, it was worse, with injuries and property damage.

I looked up the epicenter and magnitude immediately, because it was better to know than to lie awake wondering. Of course, knowing brings its own perils. That’s a 6.1 at X distance: okay. What would it feel like if it were a 6.1 in, say, Hayward, just across the Bay? Or on the San Andreas Fault, right here on the Peninsula? Actually, that one sounds scarier than it actually is; the San Andreas is more of a problem for SoCal than it is in the Bay. The Hayward Fault is the one we need to be afraid of. What if it were 7.1? The scale is logarithmic; 7.1 is not one-sixth bigger than 6.1. It’s ten times bigger. What if it were 8.1?

Not good thoughts, when you’re trying to get to sleep.

Nothing is damaged here, though Napa wasn’t as lucky. I find myself hoping that the suffering and loss of people there has a silver lining, helping motivate the local and state governments to move forward on some earthquake preparedness measures. We’re already refitting the Hetch Hetchy aqueduct, though last time I checked that isn’t due to be finished until 2016; since the aqueduct supplies most of the Bay Area’s drinking water and (pre-refit) could be thoroughly trashed by a big one on the Hayward Fault, that’s a pretty high priority. But there are other things we could be doing, and should. Sure, it’ll cost money. But we’ll lose even more when the East Bay falls down.

In the meanwhile, at least I know what a “proper” earthquake feels like. It’s good to know that, in a way: now I have facts, instead of just imagination.