Shopping carts enrolled to aid earthquake research

September 14, 1995
Web posted at: 6:05 p.m. EDT

From International Correspondent Tom Mintier

YOKOHAMA, Japan (CNN) -- Cameras designed to deter convenience-store criminals are being called on to lend a hand to science in the wake of the earthquake that killed more than 5,000 people in Kobe, Japan, last January.

People who saw video taken by the cameras got a glimpse of what it was like to be caught in the 7.2-magnitude earthquake. (1M QuickTime movie) But a professor at Yokohama City University saw something more: a chance to get important data about the quake.

Masayuki Kikuchi said that because the quake caused no break on the Earth's surface, and because there was no network of seismographs set up around the city, scientists could not pinpoint the location of the fault that touched off the damage. But on the store videotapes, Kikuchi found something that could substitute for seismographs -- shopping carts.

With each movement of the ground the carts moved across the floor, just as the needle on a seismograph moves across a piece of graph paper. (655k QuickTime movie) Kikuchi said objects such as carts, that can move in any direction, are very effective tools in determining ground movement. So he launched what became known as the shopping cart survey.

Kikuchi set out to collect video from the several hundred convenience stores in Kobe, but quickly ran into problems. Some store owners refused to provide the material, citing privacy considerations. Others said their cameras quit the instant the quake hit, when the power went out. In the end researchers got video from only 10 stores. Fortunately, those 10 stores were widely spaced around the city.

After studying the tapes, it was discovered that shopping carts in stores north of the fault line moved in one direction, while those in stores south of the fault moved in the opposite direction.

While the shopping cart survey may not shed any new light on earthquake prediction, it does provide information on the dynamics of an earthquake -- all from an unlikely source that few scientists, until now, may have thought about.

For more information, see selected articles from the LEXIS®-NEXIS® Information Service.

Related sites

• The Great Hanshin (Kobe) Earthquake
  • English version
  • Japanese version
• Earthquake Engineering Research Institute, UT Austin Student Chapter
• Recent earthquakes with maps
• Eyewitness accounts from Japanese teenagers

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