1. an instrument that detects and records earthquakes and other ground vibrations

Examples

• The seismograph recorded a magnitude 4.2 earthquake last night.
• Scientists use seismographs to study tectonic plate movements.
• The university installed a new seismograph to monitor local seismic activity.
• Data from the seismograph helped researchers locate the earthquake’s epicenter.
• Modern seismographs can detect ground movements as small as a few micrometers.
• The seismograph’s needle began moving violently during the tremor.