The question here, I think was about the day-to-day shaking, not a once in a lifetime event. Seriously if there was a 1+g acceleration who'd care if their OCXO was still running under that pile of rubble that used to be a house. It is the days-to-day level stuff that matters to time keeping even a magnitude 1.0 quake is very rare for any one building even if 1.0 is common (every day) for a geographic area. The effects are local.
hour-to-hour shaking is caused by building occupants, trucks and construction equipment and wind. But mostly things like slamming doors and such. Here is a map of recent quakes near where I live. There are quite a few but I don't know of anyone who noticed even one last week. You need sensitive instruments to detect them over the noise of street traffic and such. http://www.data.scec.org/recent/recenteqs/Maps/Los_Angeles.html All the data are there, you can look up detailed reports of each one The web site evenhas a download page where you can get "data" with accelerations, periods and such. On Mon, May 20, 2013 at 11:47 PM, Hal Murray <[email protected]>wrote: > > [email protected] said: > > If the quake is strong, the temporal acceleration is on the order of 0.1 > g. > > See: http://en.wikipedia.org/wiki/Peak_ground_acceleration > > There is a long tail on that curve. One could also define "strong" as 1 g. > > The wiki page (above) lists 3 events with PGA above 2 g and several more > above 1 g. I remember a USGS report about an event in northern California > showing a big bulldozer on its side. The punch line was that the local PGA > was over 1 g. (Bulldozers have a low center of gravity. It's hard to tip > them over.) > > Those are really nasty events. Distance from the quake (aka luck) is also > very important. If you are near one of them you will probably be worrying > about things other than your OCXO. (Iterate for what "near" means.) > > ---------- > > > Your OCXO will be fine, unless it falls on the floor. > > I agree that falling on the floor is the main thing to worry about. > > > -- > These are my opinions. I hate spam. > > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > -- Chris Albertson Redondo Beach, California _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
