👉 A seismograph is a device that measures and analyzes seismic waves. It uses the principle of superposition to measure the displacement (or variation in displacement) caused by an earthquake or other seismic event. The measurement is typically made through a microphone or other device attached to a seismograph, which sends seismic waves into the ground. These waves are then detected by the seismograph and recorded as a sequence of vibrations that travel through the earth's crust. Seismographs can be used for both