We sometimes hear from readers who ask us questions about earthquakes, and where to go on the Internet to get up-to-date information on seismic activity. While the US Geological Survey (USGS) is the first authority on earthquakes in the United States, it's actually possible now to not only turn your own computer into a seismometer, but to share that information with scientists.
The program is called the Quake-Catcher Network (QCN), and was started by seismologists Dr Jesse Lawrence of Stanford University and Dr Elizabeth Cochran of the University of California, Riverside. The software is built using the Berkeley Open Infrastructure for Network Computing (BOINC) which is is what computer scientists refer to as a distributed computing platform.
The QCN currently has some 1400 users in 67 countries, and has been used by researchers to get a clearer picture of seismic activity and fault lines in a detail that traditional seismographs cannot do.
When users run the software on their computers (available for Windows, OSX, and Linux) the seismometer doesn't actually start until the computer has been idle for a number of minutes, similar to a screen saver. If the computer experiences seismic activity, it reports it to a central server in California that gives scientists data they can use for their research in reporting seismic events.
Dr Cochran told Pameno News about the origins of the program and how it works.
"I came up with the idea to use distributed computing and MEMS sensors to increase the density of seismometers throughout the world," said project co-leader Dr Elizabeth Cochran. "Once I found out that computers had internal accelerometers I thought it would be great if we could network these computers together to create a low-cost, dense seismic network in California. As a seismologist, I am always looking for ways to collect more data that can be used to learn more about how faults rupture and the resulting ground shaking."
Cochran explained that one needed to use an Apple or Thinkpad laptop to use the software, because these computers have a built in accelerometer, which is a device that senses motion so that it can disengage a hard drive in the event that the laptop is dropped or handled roughly.
She added that people who did not own an Apple or Thinkpad laptop and wished to participate could buy a $50 USB sensor ($5 for teachers) that would allow the software to work on any computer.
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"Then", she explained, "to start detecting earthquakes, you can download free software from our website (qcn.stanford.edu). When this software is running (and your computer is connected to the internet) your computer will report any information about any strong shaking back to our server where it can be analyzed to determine if an earthquake was recorded. All of the sensor monitoring is done by the individual participant's computer, but when strong shaking occurs data is sent to a central server where it can be further analyzed to determine if it is due to an earthquake or just from someone dropping their laptop (or other noise)."
Cochran said that while false positive can occur from people dropping their computers, the network is smart enough to know an earthquake by comparing data with other users.
"Rather than heavily relying on a single station we use the large density of stations in a single area to distinguish an earthquake from other noise," she said. "So, if only one laptop in an area reports strong shaking, then we can probably ignore the data, but if many laptops in the same region report strong shaking at about the same time this suggest that the shaking is likely due to an earthquake."
With this technology, at first glance it would seem that one day private personal computers will someday replace the world's seismographs, but Dr. Cochran said that wasn't the case. While the QCN provides valuable data, it's purpose is to complement traditional seismographs, not replace them.
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"The sensors that we use are strong-motion sensors (they can only measure earthquakes M>4) and are marginally lower quality than traditional seismic instrumentation," she explained. "The high-quality seismometers used by the current networks are very important for recording the smallest earthquakes which tell us where faults are located and allows us to monitor the day-to-day activity of the fault."
If you have an Apple or Thinkpad laptop and would like to try the software, or if you you'd like to purchase a USB accelerometer, go to qcn.stanford.edu to read more about the project.
