The Inland Empire apparently had three magnitude 3+ earthquakes on Sunday night. I felt none of them, which I find disappointing, since it's been almost three months since the last one I noticed. I'm sure I would have noticed them if I had been awake, since I tend to notice even the 2.9s, and since I felt two 3.9s from the same area (near Devore) in May. I literally just missed these three, though - I went to sleep fifteen minutes before they happened, and was too exhausted to be woken up, even by the magnitude 4.0. I suppose that finishing the draft of my thesis on Sunday should have been satisfaction enough to make me feel less disappointed about missing these, but such is not the case.
I'm particularly disappointed, though, that my computer wasn't running to catch these. I've been alpha testing the Quake-Catcher Network software since the beginning of February, and I have not yet had a chance to see how it picks up a genuine earthquake or three (as opposed to the motions caused by cats named after faults rocketing around my apartment). Also, by having one less of the alpha test computers running at the time (not that I know how many were running), that's less data with which to test the collecting and analyzing part of the QCN software. I know one computer isn't going to screw it up all by itself, but since I'm trying to help test this thing, I know my computer will be more useful if it was turned on to pick up quakes, even if I'm not awake to feel them. I'm hesitant to leave the computer running 24/7 for the sake of my hard drive, but I may have to just not think about that.
Looking at this little sequence (4.0, 3.4, 3.2) and one from 23 May 2007 (3.9, 3.9), both centered in pretty much the same place near Devore, I have to wonder if there's a small asperity in the fault there. In both sequences, all of the events happened within a couple of minutes - if not seconds - of each other, without many aftershocks later. I admittedly don't know enough about fault mechanics yet to tell whether or not my thought here can hold any water, but it seems at least possible that in these sets of events, the rupture could start, be briefly paused by the little asperity, then continue after stress makes the asperity give way. Does this actually make sense? Now that there have been two little sets of events there, I plan on reading more about that aspect of fault mechanics once I'm done with my comprehensive exams.