A tiny temblor that registered a 3.2 magnitude struck Berkeley at 1:07 a.m. last night, disturbing most light sleepers and perhaps confusing those who were still awake marathoning House of Cards.
The quake struck 2.5 miles northeast of Berkeley, at a depth of 4.5 miles, and this follows on another quake of a similar size that struck in the same vicinity on October 6. Of course little quakes like this are perfectly normal and healthy for the shaking out of tensions in our fault lines, but the paranoid among us like to start to see patterns. And, of course, the Hayward Fault is due, as we all know.
Last night's was followed by four smaller aftershocks that went on until after 2 a.m.
The last, biggest quake to hit the Hayward Fault, which runs all the way under the length of the East Bay to San Pablo Bay, was in 1868, and it was a 6.5-7.0 magnitude and ended up killing 30 people despite the population being a fraction of what it is now.
For those who would like to amplify their paranoia this morning, the USGS has created this pretty animation illustrating how the intensity of the shaking would spread along the fault in the East Bay and out to the San Francisco in the event of a 7.0 quake centered in San Pablo (see still above, and despite the government shutdown, this portion of the USGS site still functions). They also have versions for an Oakland epicenter, and a Fremont epicenter. In all cases, the shaking will be felt pretty hard in the city (level 6 to 7 out of 10), however the East Bay will get the brunt of the intensity.