A rare East Coast earthquake that shook people from North Carolina to Boston today prompted heavy call volume that jammed cell phone networks throughout the region.
Instead of calling, many residents eager to share their experiences and get in touch with loved ones and friends reached out sites like Twitter and Facebook.
The quake, measuring 5.9 on the Richter scale and centered in western Virginia, struck at little before 2 p.m. ET. There were no initial reports of major damage, however, buildings like the Pentagon in Washington, D.C., and New York City Hall were partially evacuated.
Cell phone voice service was disrupted especially in major cities, such as New York and Washington, D.C., according to Twitter users. Regular phone lines seemed to be working fine. And text messages also seemed to move through the network. But for some, data service was sluggish and voice-mail messages were also delayed. For people trying to make phone calls or receive them on their cell phones, service was spotty at best.
A representative from Verizon Wireless said that its network had no structural damage, but that heavy call volume was disrupting service for some customers.
"We are seeing no reports of damage to our wireless network, which is built for reliability in situations like this," the representative said in a statement. "There was network congestion for some customers in parts of the East for approximately 20 minutes after the tremors. Everything returned to normal quickly once the tremors ended. We'll continue to monitor the network."
Sprint Nextel also said that its network was not damaged, but that heavy call volumes may have disrupted service temporarily.
"We are currently experiencing an intermittent mass calling event as is expected following an incident of this nature," the spokesman said. "There are no reported physical impacts to our networks and we encourage customers to be patient, and send a text message rather than call at this time if they need to reach family and friends."
Indeed, text messaging is the best way to communicate during an emergency an event that will likely cause a large number of people to make phone calls at once. Most wireless networks are not designed to sustain an onslaught of phone calls all at once. Wireless networks are shared and when too many people try to use the resources at the same time, the network blocks calls or drops calls in an effort to make room for more requests. This is especially true for voice calls, because those connections need to be maintained.
Text messaging is a better way to communicate during or following a crisis or event when network congestion is high for two reasons. First, SMS text messaging uses far less of the network resources than a voice call or wireless broadband data session. And second, even when the network is congested, the SMS system will continue to keep trying to send the text message, even if it gets a "busy signal" on its first try. Also the bits of data in the message don't need to travel together on the network, like with a voice call. This makes it a more efficient and easier way to communicate when the network is severely congested. But even SMS messages can be delayed, so wireless operators also urge people to be patient.
For East Coast residents with little direct experience with earthquakes, Twitter and other social media were the first ways to confirm that what they had just felt was, in fact, a significant earthquake.
Within moments, the United States Geological Survey confirmed everyone's questions, showing maps, strength, and how the intensity of tremors across the affected area.
In less than an hour, the USGS also had nearly 2,000 responses to a citizen scientist application called "Did you feel it?" People submitted information about how long the tremors were in their location as well as detected damage.
For people not used to tremors, Internet-based media was a natural avenue to find out more. One person on Twitter noted that it took less time to learn about the earthquake on the Internet than to leave the building.
Social-networking sites also served as a way to communicate with loved ones and friends as the cell phone networks were not working.
CNET senior writer Roger Cheng contributed to this report.
Updated: This story was updated with carrier statements and additional background.