Science Olympiad Dynamic Planet Practice Test

What device is used to record ground movements caused by seismic waves?

1. Accelerometer

2. Seismograph

3. Seismometer

4. Tachometer

The correct answer is: Seismograph

The device that is primarily used to record ground movements caused by seismic waves is a seismograph. This instrument works by detecting vibrations in the ground that result from seismic activity, such as earthquakes. The seismograph typically consists of a mass suspended from a fixed base, and as seismic waves travel through the Earth, they cause ground motion that moves the base while the mass remains relatively stationary. The relative movement is recorded on a rotating drum or digital medium, producing a seismogram that depicts the intensity and duration of the seismic waves. The terms seismometer and seismograph are often used interchangeably; however, in a strict sense, some might argue that seismometer refers more generally to the instrument that detects and measures ground movements, while seismographs provide a visual representation of those measurements. Nonetheless, seismograph is the more commonly recognized term in the context of recording seismic waves. An accelerometer is designed to measure acceleration and is often used in various applications outside of geology, while a tachometer measures rotational speed. Therefore, these devices do not specifically serve the function of recording seismic activity.