Which instrument is used to detect and record seismic waves?

• A. Richter Scale
• B. Modified Mercalli Scale
• C. Seismometer
• D. Seismoscope

Answer: (C)

Seismic waves are ground vibrations produced by earthquakes, and the instrument that detects and records those waves is a seismometer. It senses motion of the Earth's surface and converts it into an electrical signal that is recorded as a seismogram, showing when waves arrive, how strong they are, and their frequencies. This lets scientists analyze the quake’s size, duration, and the structure of the Earth's interior. The other options aren’t used to detect and record waveforms: the Richter scale measures magnitude, the Modified Mercalli Scale rates shaking intensity and damage, and a seismoscope only indicates that shaking occurred without providing a detailed record.