STANFORD, CALIF. — Six thousand tiny seismic sensors are seeking homes — or offices, or classrooms — where they can take up residence. The matchbox-size sensors are part of a new phase of the Quake Catcher Network, a project that is building the densest networks of seismic sensors ever devoted to studying earthquakes. All it takes to volunteer is a computer, an Internet connection, and a small patch of floor space.
The first roll-out of the sensors will begin July 9 and 10 in the San Francisco Bay Area, where volunteer installers will be available to deliver 200 sensors to people who sign up to host one. The researchers hope to install more than 500 sensors in the Bay Area this year, shipping the majority to hosts for self-installation. QCN is developing complementary networks in Southern California, the Pacific Northwest, Anchorage, Salt Lake City, and Memphis.
"With thousands of volunteers hosting our seismic sensors, forming dense networks in these regions, we’ll be able to get data on a level of detail and with a degree of accuracy that we could only dream about before," said Jesse Lawrence, assistant professor of geophysics at Stanford University, where the project is based.
Targeting ‘earthquake country’
These regions were chosen because of their proximities to faults that have the potential to generate major earthquakes of magnitude 6.7 or above. The 1994 Northridge earthquake in Southern California was a magnitude 6.7 and the 1989 Loma Prieta earthquake in the Bay Area was a magnitude 6.9.
Lawrence, along with Elizabeth Cochran, a research geophysicist at the United States Geological Survey, came up with the original plan for the large networks of tiny sensors. Since then, researchers at the University of California-Berkeley, California Institute of Technology, University of California-San Diego and the University of Delaware have joined the effort.
For the Bay Area network, researchers are especially interested in locating sensors near the Hayward Fault, which runs roughly northwest-southeast through the East Bay. It is considered the fault most likely to generate a major earthquake in the Bay Area within the next 30 years.
Maps of the target areas in the Bay Area and other parts of the country are on the project’s Web page so interested volunteers can get a rough idea of whether they might be eligible to host a sensor.
"This network will help us better understand the earthquake process, how the shaking that causes most of the damage radiates from the epicenter of the earthquake, and how to reduce the impacts of earthquakes," said Richard Allen, the director of the UC Berkeley Seismological Laboratory, who is participating in the project.
Because the sensors are constantly on the job, they will be able to send data to the project’s server while an earthquake is happening. Soon, the server will be able to send out electronic notifications to anyone who has signed up to get the Quake Catcher mobile phone app or computer program.
"Seismic waves travel slower than Internet traffic, so notifications could reach some participants before the seismic waves do," said Cochran. "We are still investigating how reliable and accurate this process will be."
Half of the sensors are reserved for educational purposes and are available to K-12 teachers who apply to the program. The Quake Catcher team provides free educational software to help teachers demonstrate how earthquake motions are detected and monitored.
"With more sensors in high-rise buildings, earthquake engineers will be able to monitor the response of the buildings to earthquake shaking on spatial scales not currently possible" said Monica Kohler, a senior research fellow at Caltech.
What you need to volunteer
To volunteer, you need to have a computer, about five years old or less, running a Windows or Macintosh operating system, with a spare USB port to which the sensor can be connected. You’ll need a high-speed Internet connection so that data from the sensor can periodically be sent to the project’s server.
You also need to provide a space on your floor barely larger than a small Post-it Note for mounting the sensor.
Your computer will provide power to the sensor, monitor any strong seismic shaking, and upload data to the server when it recognizes a strong new signal that might be earthquake-related.
The software runs in the background, typically using a very small amount of computing power.
The sensors only work when the computer is on, so priority will be given to hosts with 24/7 computer usage with battery backup.
Installing a sensor takes just a few minutes, requiring only a quick dab of adhesive to attach the sensor to the floor while the computer is downloading the network’s free software. The sensors can be easily removed.
"We’re looking for people to host the sensors for the duration of our project (three years), but we’ll take any volunteers willing to host these sensors for over a year," Lawrence said.
The Quake Catcher team has already installed more than 2,000 of earlier versions of the sensors in 67 countries around the world. The largest/densest networks were installed in Chile and New Zealand, both earthquake-prone countries.
The older sensor models could detect a magnitude 2.6 earthquake at a distance of approximately five kilometers. The newer models, developed by O-NAVI, are more sensitive.
The Quake Catcher Network operates on the Berkeley Open Infrastructure for Network Computing, which is the underlying architecture for dozens of scientific projects.
Other researchers integral to the Quake Catcher Network are Tom Heaton at the California Institute of Technology, Jack Baker and Carl Christensen at Stanford, Debi Kilb at UC-San Diego, and Michela Tauffer at the University of Delaware.
The project is supported by the National Science Foundation.