This cage still surrounds the Washington Monument after the August, 2011 quake. During that quake, there were more than 4,000 tweets per minute mentioning it. Photo: USDA
When people feel the ground shake, they talk about it.
That's never been more clear than when an earthquake struck Washington, D.C. in 2011. Even considering DC's nerdy, tweet-happy population (I'm guilty here), the 4,000 tweets per minute in the direct aftermath of the quake was pretty impressive.
And it wasn't the United States Geological Survey, CNN, or another major news organization that first reported (in English) the magnitude 7.9 earthquake that shook Wenchuan, China in 2008. It was none other than Roger Scoble who happened to see people who felt the quake tweeting about it.
“I reported the major quake to my followers on Twitter before the USGS website had a report up and about an hour before CNN or major press started talking about it,” Scoble wrote in a blog post about the experience.
Researchers took notice: After that quake, USGS, which has more than 7,000 ground sensors all throughout the United States and the world designed to pick up seismic activity, decided to see if they could build an algorithm that can alert them to earthquakes before their sensors can.
Turns out, they can do it pretty well. By measuring the uptick in people tweeting the word "earthquake" in several different languages, USGS can usually—in more than 75 percent of cases—tell whether an earthquake has occurred within two minutes of it striking. In some cases, the first tweet after an earthquake happens less than 20 seconds after an earthquake strikes (kids these days are so fast with their phones, aren't they?). By comparison, it can take up to 20 minutes for a sensor in a rural area to relay that information back to USGS.
USGS' TED tracks tweets per minute that mention the word "earthquake"
"Every minute really counts for some of the emergency responders," Jason Young, who works on USGS' Tweet Earthquake Dispatch system. "In more remote locations in the US and in international areas, it can take up to 20 minutes for the sensors to activate, which can be quite important in a life-or-death situation."
A report released this week by DC's Woodrow Wilson Center details how "citizen seismology" is changing how USGS and first responders handle earthquake detection. Instead of simply waiting for a sensor to go off, a seismologist like Paul Earle, who developed TED, will get instant texts to his phone as soon as the algorithm detects a frenzy of people using the word "earthquake."
While there's all sorts of problems with using only TED, such as the fact that a lot of the people using Twitter aren't geotagging their tweets, it can be a good first tool for people at USGS.
"Once the TED application detects an earthquake, it automatically produces alerts that are sent internally to the USGS duty seismologists and cooperating response agencies so that the National Earthquake Information Center can turn to more scientific data sources for confirmation of the earthquake," the report says. "More broadly, citizen seismology is advancing earthquake science, because it allows scientists to collect data about earthquakes even in locations where sensors are sparse or even absent altogether."
There are, of course, lots of kinks that still need to be worked out, and there's also a lot of things your tweeps can't tell you that a sophisticated sensor can. While tweets may be faster at detecting earthquakes, it's obviously can't detect an earthquake's magnitude or impact range—unless you're good at translating "holy shits" to the Richter Scale.
Twitter, more than Facebook, is still largely an American phenomenon—about a quarter of all Twitter users are American, which makes it tougher for TED to detect earthquakes in Bangladesh. During TED testing between August and November 2009, it detected only 48 earthquakes; seismometers detected 5,175. That's not great, but because you're not going to tweet if you barely feel a nearly imperceptibly small earthquake, it's not that big of a deal in terms of getting the word out during a bigger disaster.
So hey, next time you feel a big quake, jump under your desk, but take your iPhone and tweet about it, you might actually be helping out.