JAMES KING-HOLMES / SCIENCE PHOTO LIBRARY JAMES KING-HOLMES / SCIENCE PHOTO LIBRARY
Willmore seismometer for monitoring earthquakes. A magnet is suspended within coils of copper wire (two seen). During an earthquake, these coils move about the fixed magnet and disrupt its magnetic field. This induces an electric current in the coils, providing information about the earthquake. Big earthquakes induce larger electrical currents. It specifically measures the speed (velocity), and not the acceleration of the ground movement. It is a short-period seismometer, suitable for measuring rapid vibrations with a frequency of less than 3 seconds. Changing its alignment allows measurement of vertical or horizontal motion. The small size and handle allow it to be carried to remote areas.
Model release not required. Property release not required.