Teensy little quake

[hrj]

The last several quakes I've felt have been centered very locally, so I was guessing that this one was maybe around a 3 -- just enough to make the bookshelves creak slightly. But evidently it was a 5-something down in the South Bay. The anecdotal commentary so far suggests the local effects were really variable. Perhaps some odd propagation patterns?

Comments

[patsmor.livejournal.com]

Thanks for that description -- it was very helpful.

What constitutes "distant?" 15 miles? 150?

[albionwood.livejournal.com]

Hmm, good question. It has to be far enough that the difference in travel time for the waves is noticeable. Loma Prieta was, what, about 70 miles from Emeryville? I doubt you could generally feel the difference at distances of less than 30 miles or so. But this quote from a Chron article pretty well describes what I'm talking about:
"First there was some up-and-down shaking, and then it went side-to-side, but it was nothing like '89,"
and he was in SJ, about 25 miles from the epicenter.

[patsmor.livejournal.com]

That's good to know, and it explains what I felt -- first a sharp jolty motion, and then a side-to-side, almostly hammock-y. I'm in Mountain View now, and the calculator on the USGS service says that put me about 18 miles from the epicenter (31 km).

[hrj.livejournal.com]

Whereas I didn't feel any jolt -- just a subtly growing creaking/shaking with a second pulse of that just as it was dying down. (I was amused to have that last observation validated by other people describing a secondary "pulse" right at the end.) I have the advantage of not being on landfill (just barely -- the filled area is the west side of the railroad tracks, which is only about 4 blocks away).

[patsmor.livejournal.com]

I felt the last "pulse" before the end, too. It was what made me wonder if I should get out of bed and do something more active about my situation ;-)

I know my neighbors' upstairs had something fall -- I heard it go over.

Of course, all the folks at work who lived nearer the epicenter had much more energetic stories to tell today.