What device is used to detect and record earthquakes?

A seismograph is the device used to detect and record earthquakes. It measures ground motion and produces a record called a seismogram, allowing scientists to study when and how strongly the Earth moved.

Traditional seismographs used a heavy mass suspended from a frame. When the ground shook, the frame moved while the mass tended to remain nearly still because of inertia. The difference in motion could be traced on paper. Modern instruments use electronic sensors and store digital data, but the basic principle remains similar.

“Seismometer” is closely related and is often used interchangeably with “seismograph.” More precisely, a seismometer is the sensing instrument, while a seismograph generally includes the recording system. A thermometer measures temperature, and a barometer measures air pressure. By comparing records from several stations, scientists can locate an earthquake’s epicenter and calculate its magnitude.