Not So Fast

Last year the webcomic xkcd compared the speeds of seismic waves and internet traffic (I was alerted to it by a tweet yesterday).

Here’s one of the jokes that’s doing the rounds about the earthquake in Virginia:

DC Earthquake Devastation

It’s been viewed on one site more than 2 million times and tweeted nearly 47,000 times. The blogger who put it up there took it from here, which has been mentioned on Twitter only 555 times, but it seems to have first appeared here (2014 tweets).

Not many people seem to have noticed, however, that it’s been on the internet, on all three of those sites, since 16 July 2010, when Washington DC was hit by an earthquake of magnitude 3.4 – considerably weaker than yesterday’s.

‘Our understanding of active fault structures in the densely populated northeast leaves much to be desired,’ Susan Elizabeth Hough wrote in Earthshaking Science. Still, ‘damaging ground motions are expected on average every 1000 years or so in New York City. A calculation for other parts of the northeast… yields a similar result.’