This sure doesn't seem like the winters we used to have. But as long as they're able to hold the derby we don't care.

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Seismometers are just like microphones. They're buried in the ground and, when the earth shakes, they generate a current that goes via telephone lines or the Internet to a computer system that reads the arrival time and size of the shaking. If you have several seismometers, you can determine the location and magnitude of an event.

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