Followup on Yesterday's Virginia Earthquake

Since I posted yesterday in the wake of the magnitude 5.8 earthquake in northern Virginia, new information has come up. Perhaps most obviously, the magnitude has been slightly revised downward to 5.8. (See current details at the US Geological Survey's special page for this event.) Technically this may mean that yesterday's event is not really the largest in Virginia's history. But the whole thing is hard to tell because the "5.9" event in 1897 was estimated many decades later from published reports of felt shaking and building damage—that is, intensity data—whereas the 2011 quake is gauged by seismograph records for a much more accurate determination of magnitude.

Some damage has been documented in Washington DC, most notably the fall of some decorative rockwork and buttress cracks on the National Cathedral. The usual broken windows and collapsed grocery displays occurred all around the epicentral area. Remember that the East Coast isn't all ancient brick structures. Modern engineered buildings take earthquakes into account. And besides, older buildings very often were designed to withstand lateral loads from the occasional hurricane, adding to their quake resistance. The late 19th-century downtown buildings of San Francisco were designed this way, and they weathered the 1906 earthquake quite well (just not the fire that followed).

For another thing, a comparable earthquake (magnitude 5.3) struck southern Colorado earlier in the day, the largest there in 44 years. It was felt throughout Colorado and in northern New Mexico. Finally, at 11:37 that night a magnitude-3.6 banger happened practically underneath my own house—just a reminder for West Coasters not to be complacent or condescending, I guess.

Other About.com Guides have been blogging about the quake:
Pet Supplies Guide Barbara Nefer passed along word on the behavior of the animals at the National Zoo.
Catholicism Guide Scott Richert urges his readers to pray for those affected by the quake. I should add that Catholics may appeal to Saint Emidius, who is the patron saint of earthquakes.
Rachel Cooper, About.com Guide to Washington DC, reports on local effects and damage.
Financial Software Guide Shelley Elmblad takes the occasion to help us think about inventorying our possessions for insurance purposes.
And Nancy Parode, the Senior Travel Guide, points out that any of us might find ourselves in earthquake country during our travels. Follow her link to travel advice, too.