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Add your Apple computer to the 'collective'

May 5, 2008

by Mark Ollig

What’s the latest tool researchers are using to measure the shakes and tremors caused by an earthquake?

Imagine detecting those vibrations and other ground shaking disturbances using your Apple laptop computer.

Back in 1996, Apple Computer began to incorporate “Sudden Motion Sensor” technology into many of their new Macintosh laptops.

This technology is also known as a “Tri-axis Accelerometer” and “Mobile Motion Module.”

It is being used by Apple as built-in protection for the computer’s hard disk.

This motion sensor was designed to help prevent disk failures if the computer was dropped or underwent severe vibrations.

The motion sensor is used to detect unusually strong vibrations . . . sudden changes to the computer’s position or any quick movements.

For example, if the computer is dropped, the motion sensor instantly “parks” the hard drive heads in order to reduce the risk of damage and to save its data.

When this motion sensor “senses” the computer’s condition is once again stable, it will unlock the hard drive heads, allowing the computer to once again work normally.

The “Quake-Catcher Network is a shared project for developing the worlds largest and most cost-effective seismic motion network.

This network taps into those motion sensors inside the computers connected to the Internet. Their web site is at http://qcn.stanford.edu.

Currently, only the Apple computers (including the newer MacBook’s) which have this motion sensor built-in and can participate in the Quake-Catcher Network program.

Work is being done on developing an accelerometer motion sensor which can be plugged into a non-Apple computer using a USB flash drive, allowing these computers to also participate.

About 300 folks from around the world are taking part in the Quake-Catcher Network, with roughly a third of the participants in the United States.

Researchers with the Network for Earthquake Engineering Simulation Cyberinfrastructure Center or “NEESit” at the San Diego Supercomputer Center wrote a new software interface application.

This software programs merges the “tri-axis accelerometer,” or sudden motion sensor, with the “iSight” video camera that’s used in newer Intel-based chips the laptops use for videoconferencing.

Under a grant from the National Science Foundation, free downloads of the SeisMac 2.0 software are available to turn Apple’s laptops into real-time seismographs.

The San Diego Supercomputer Center (SDSC) iSeismograph project is making available to researchers the data acquisition systems for analyzing these measurements using a commonly available laptop computer.

SDSC researchers have already conducted a pilot classroom project with about 90 University of California, San Diego (UCSD) students participating as part of an undergraduate earthquake engineering course.

The students benefited from the demonstrations by measuring actual earthquakes, enabling researchers to suggest classes for future demonstrations and study.

SDSC researchers found a way to link the existing accelerometer and video sensor in all newer Macintosh laptops to its NEESit Real-time Data Viewer (RDV), which provides a graphical display of the movement on the computer.

The RDV was linked to a higher level software applications system, which was funded by the good folks at the National Science Foundation. This system is used for sensor-based observation of environmental events like earth movements and for collecting weather data.

When data from an event is captured in the Data Turbine server’s archive, it is automatically transferred using the laptop’s wireless network interface into the NEES central database storage, where students and researchers can work together on a worldwide scale by investigating, processing and sharing information.

NEEScentral is a high-level data storage version that is available to all earthquake engineering branches and contains information on how to archive and share the data.

“We’re turning the laptops’ accelerometers into earthquake monitors,” said Elizabeth Cochran, assistant professor of seismology in the Department of Earth Sciences at the University of California, in Riverside.

“The idea is to fill in the spaces – or holes – in the seismic network currently being used to report earthquakes,” Cochran said.

Cochran concludes, “With a dense grid of detectors in place, an early warning can be sent through the Internet to neighboring cities should an earthquake strike, giving people up to 10-20 seconds to prepare themselves before the seismic waves reach them.”

For more information, check out Elizabeth Cochran’s web site at http://ep.ucr.edu/EP/Cochran/Home.html.

If you own an Apple computer and want to join the collective, you can download the software for free by accessing it online at http://it.nees.org/software/iSeismograph.

The website for NEESit is at http://it.nees.org.

The University of California San Diego web site is located at http://www.ucsd.edu.

The San Diego Supercomputer Center is at http://www.sdsc.edu.