Earthquakes create seismic waves which the seismograph records by when a seismic wave reaches the place where the seismograph is the seismograph shakes.The seismograph records the energy of the seismic waves having 2 magnetic poles connected to each other then there is a string hanging from the 2 metal poles .Then there is a metal ball or just a ball hanging from the string with a piece of lead connected to it.There is a piece of paper under the lead so when the seismograph shakes the piece of lead will record the energy of the seismic waves.