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Earthquakes: Seismographs A long, long time ago

Choko and his seismograph This early eastern seismoscope consisted of a copper vessel with eight dragon heads attached to it, positioned above eight frogs.

Each dragon head held a ball in its mouth, which, when dropped due to the strong shaking of an earthquake, would fall into the open mouth of the frog directly below it.

By noting which frogs contained balls after a strong earthquake, it was possible to determine how the Earth had moved in response to the earthquake.