March 6, 2012
Stanford's Quake-Catcher Network detected Monday's tremor 10 seconds before the shaking reached campus
The Quake-Catcher Network, a web of sensors plugged into the computers of 2,000 volunteers, detected the shaking of Monday's 5:33 a.m. earthquake in less time than it took the motion to travel through the ground from the epicenter in the East Bay town of El Cerrito to the Stanford campus in Palo Alto. The detection system runs on relatively inexpensive sensors, and could provide a few extra seconds for people in an earthquake zone to duck under a desk.
By Steve Tung
Stanford geophysicist Jesse Lawrence explains how low-cost seismic sensors could help create an early warning system for earthquakes. The Quake Catcher Network is a collaborative effort among five academic institutions and the US Geological Survey. (Photo: Steve Fyffe / Stanford News Service)
Did you feel the 4.0 magnitude earthquake near Berkeley Monday morning?
Stanford's Quake-Catcher Network did, detecting it 10 seconds before it hit Stanford. Unlike other earthquake detection systems, which use high-cost sensors, QCN uses many low-cost sensors plugged into volunteers' computers.
If you want to participate in the program, click here. The network provides free sensors to those who live near faults and a $49 version for those who live outside of those areas ($5 for K-12 teachers).
"The front that we've been pushing recently is to try to detect earthquakes more rapidly," said Jesse Lawrence, the project co-founder and an assistant professor of geophysics at Stanford. "The concept is ultimately to get to the place where we can reliably identify and characterize earthquakes before they've expanded to the surrounding regions."
Lawrence emphasizes that QCN is not an early warning system (only the government can issue warnings in the United States), but he hopes that it will eventually provide informative, real-time notifications via digital media to many earthquake-prone subscribers before an earthquake's strongest shaking. The system may notify them anywhere from zero to tens of seconds before the earthquake hits them.
"We often get the question, 'What's a second worth?' " said Lawrence. It's a valuable extra bit of time to "stop, get down underneath a desk or a safe spot, and hold on."
"I don't know about you, but the last time I felt an earthquake, I asked, 'Huh, is this an earthquake? Oh, yeah, it is an earthquake,' " said Lawrence. "So there's a couple seconds that go by. Then I get under the desk kind of timidly, thinking, 'If this isn't an earthquake, I feel kind of dumb getting underneath the desk.' I don't move as quickly as I should."
With QCN's planned system, users will get quick post-quake notification of an earthquake's magnitude and duration. Also, the warning can be used to automatically alert elevators to let passengers out at the next floor, or for companies to turn off sensitive electronic equipment.
The system uses sensors that plug into the USB port of computers and communicate with servers at Stanford over the Internet. Traditional earthquake sensors cost $3,000 or more, but the network uses sensors that cost the organization only $30 to $150. This means that QCN can potentially have far more monitoring sites than traditional networks.
Currently there are about 2,000 volunteers in the network. Additional sensors will improve the network's ability to determine the precise movements of a quake. Greater coverage also means that the group can detect earthquakes sooner, and give more precise estimates about the spread and magnitude of the quake. The data can also be used to better understand what goes on at the site of the fault.
"There's amazing amounts of science that one can do with lots and lots of sensors, science that's much harder to do when you have fewer sensors," Lawrence said.
The low-cost sensors used in QCN are also promising for use in developing countries.
"This network is going to be the only type of network that you're going to get in a country that can't afford a [traditional] network," Lawrence said. "For the price of one really good sensor, you can get 100 to 1,000 USB sensors."
The National Science Foundation-funded project has collaborators at the U.S. Geological Service, the Los Angeles and Berkeley campuses of the University of California, the California Institute of Technology and the University of Delaware.
Steve Tung is a science-writing intern at the Stanford News Service.