In earthquake country, familiarity breeds ... yawn.

I'm told we had a moderate earthquake here last night. Indeed, it is reportedly the largest earthquake in the area since the 1989 Loma Prieta quake -- which, as it happens, was the temblor that welcomed me to the San Francisco Bay Area.

I completely missed it.

You see, I was driving home from the store with the carrot sticks for the younger Free-Ride offspring's classroom Hallowe'en celebration. The roads haven't been repaved in a while, so I suppose the jostling that I attributed to the road surface might have been caused in part by seismic activity.

At home, the sprogs felt the shaking (although at first they thought that my better-half might have been causing it). Dozens of miles away, Uncle Fishy felt it (and called to see if we had felt it, too). A bunch of people stopped what they were doing to report their experience of the quake to the USGS.

But it's hard not to wonder how much our perceptions of these seismic events are colored by our prior experience. Looking at the estimated severity of the quake reported by folks much further from the epicenter, we asked each other, "Do we tend to underestimate how long or how violently things shake?" We've lived in earthquake country a long time, and we know that most of the shaking just lets out some stress. Generally, there's not any damage. At Casa Free-Ride, nary a book fell from a shelf. At my office, I noticed a few items on my desk that must have fallen from my shelves -- a framed picture, a stack of Post-It notes, a container of red pepper flakes from the pizza joint -- but it was hardly a disaster scene.

Which means we'll probably continue to be pretty nonchalant about the faultlines crisscrossing our region, even though the Hayward fault is averaging a major earthquake every 140 years, and we just passed the 139th anniversary of the last one.

Undoubtedly, part of our nonchalance has to do with the fact that seismic retrofitting became a serious issue after the 1989 quake, and that earthquakes are so much a part of the standing conditions in these parts that construction has assumed they would happen. Our houses, by and large, are built to ride out the rumblings.

But part of it probably has to do with the fact that it's really hard to predict earthquakes in the same way you predict rainstorms, or even firestorms. Despite what people might tell you (on the basis of a couple memorable quakes), there is no such thing as "earthquake weather". You don't get a tip-off in the five-day forecast.

They hit, and then they stop. The shaking itself seldom lasts more than a minute.

There's something about this state of affairs that leaves me feeling almost negligent. I'm taking for granted that for the most part temblors won't cause major disruptions in our lives, and that in the cases that they might, there's not a heck of a lot we could do to prevent them.

A really big earthquake could wipe that complacence right off my face. But short of leaving the area, I'm not sure what a reasonable person should do in the light of the knowledge that a really big earthquake will, eventually, happen here.