NEW YORK (CNNMoney) -- When the ground starts shaking, the tweets pour in.
The 5.8-magnitude earthquake that struck near Washington, D.C., at 1:51 p.m. caused a rumble across the East Coast and within the social media realm. Within seconds, people took to Twitter for confirmation.
"Anyone else not notice/feel anything at all? #earthquake #NYC," user @davetisch tweeted.
Twitter streams filled with a range of #earthquake Tweets -- everything from 140-character messages about rumbling buildings to shaky humor.
"I don't remember being *this* bad at Jenga," @bazecraze quipped.
Trending topics included "5.8" and "Earthquake in DC" and "FELT IT." Twitter held up under the deluge -- its famous Fail Whale never appeared -- but its network slowed slightly. Five minutes after the quake hit, Twitter's average response time doubled from 2.16 seconds to 4.17 seconds, according to monitoring site AlertSite.
As tweets poured in, thousands of Foursquare users checked in to an event created specifically for the earthquake called "Earthquakepocalypse," which became the location-based social network's fastest venue to hit 10,000 check-ins.
Social media users also took to Facebook. Right after the quake, "we saw the term 'earthquake' appear in status updates for nearly 3 million people on Facebook in the US," a Facebook representative told CNNMoney.
After the quake, cell service along the East Coast was spotty for about half an hour, so the Department of Homeland Security took to Twitter to encourage people to use e-mail and social media to reach out to friends and family.
New York's MTA transit system also used the microblogging service to update commuters. "There are no impacts to subway, bus or LIRR or Metro-North service as a result of the earthquake," they tweeted.
It's yet another example of social media's increasingly important role in chronicling unexpected events.
"Regular people can document real-time experiences and broadcast news simply using personal mobile devices," said Sav Banerjee, strategy director of digital ad agency Rokkan. "Twitter single-handedly creates a domino effect of real-time reporting, enabling the world to share news quickly and effectively using multiple mediums -- photos, videos, text -- as it happens." 
