CLAUS LUNAU / SCIENCE PHOTO LIBRARY CLAUS LUNAU / SCIENCE PHOTO LIBRARY
Seismometer. Artwork showing the basic principle of a seismometer, a device used to record earthquakes. A heavy weight (spherical) is suspended on a spring. During an earthquake, the apparatus moves while the heavy ball remains suspended in mid-air. This causes the pen attached to ball to record a trace on the paper at right. This paper winds onto and off a cylinder that rotates at a constant speed, resulting in a trace (red) of the earthquake's amplitude.
Model release not required. Property release not required.