A seismometer is an instrument used to detect and measure the vibrations caused by earthquakes and other seismic activities. It works by using a mass suspended on a spring, which remains stationary while the ground moves during an earthquake. The movement of the ground causes the mass to shift, and this motion is recorded as a seismogram. Seismometers are essential for understanding the Earth's internal structure and for monitoring seismic activity. They help scientists, such as seismologists, analyze the strength and duration of earthquakes, which can improve safety measures and inform emergency response efforts.