Seismograph
Emily K.
http://www.seismo.unr.edu/ftp/pub/louie/class/100/seismic-waves.html
Seismographs are used by scientists who study earthquakes. When the ground shakes, the base and frame of the seismograph moves with it. Essentially sound waves are radiated from the earthquakes as it ruptures. A seismograph is an instrument used to detect and record P waves and S waves produced by earthquakes. Seismic waves are shock waves, which are actually waves of energy. Earthquakes produce two types of seismic waves at the same time, the P waves and S waves. These waves are detected and recorded by the seismograph.
