TweetQuake

This is a joint post with Alan Mislove, based on our work with Yong-Yeol Ahn and Chloe Kliman-Silver.

On on August 23, 2011, at 1:51 PM EDT a magnitude 5.8 earthquake hit the Piedmont region of the U.S. state of Virginia. Orders of magnitude smaller than the recent earthquake in Japan, this quake was nonetheless the largest in the U.S. east of the Rocky Mountains in 114 years (according to Wikipedia).

But why are we talking about earthquakes? We should be talking about people talking about earthquakes. And people really did some talking. The official twitter account (@twitter) posted three back-to-back tweets on the subject:

Are Tweets faster than seismic waves? We can’t speak to speed of seismic waves, but a Tweet can reach your followers in less than a second. [link]

Within a minute of today’s #earthquake, there were more than 40,000 earthquake-related Tweets. [link]

And, we hit about 5,500 Tweets per second (TPS). For context, this TPS is more than Osama Bin Laden’s death & on par w/ the Japanese quake. [link]

Now, as I am sure many people have already pointed out (e.g. on twitter), this situation was deftly analyzed and anticipated by Randall Munroe, author of the wonderful webcomic xkcd back in April 2010. Here’s the strip:

seismic_waves.pngAs Munroe points out, the speed of “damaging” seismic waves is around 3-5 km/second, which is much slower than the speed of information spreading on the internet. This simple fact means that if you’re more than 100 km away from the epicenter you can read about the quake on twitter before it hits you.

Now, combine idea from the xkcd strip with data from the tweetquake and it’s possible to observe this phenomenon in practice. In the visualization below, we’ve generated a video of the mentions of the work “earthquake” in tweets from the gardenhose in the 5 minutes immediately following the earthquake. For simplicity, we have assumed a uniform 4 km/s wave and ignored deformations due to map projections, etc (we’re not geologists, after all).

The comic strip doesn’t factor in the time it takes to actually write a tweet, and since seconds count, it takes more than 100 km before we see tweets posted outside the wavefront (validating the last frame of the comic strip). It is awe inspiring to see a truly real time news medium in action.

Notes:

Published by

Sune Lehmann

I’m an Associate Professor at the Department of Applied Mathematics and Computer Science, at the Technical University of Denmark.

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