The machine used to measure earthquakes is called a seismometer, or seismograph. This instrument detects and records the vibrations produced by seismic waves as they travel through the Earth during an earthquake. Seismometers can range from simple, mechanical devices to highly sensitive electronic instruments that provide detailed information about the intensity and duration of seismic activity. The data collected by seismometers help scientists understand the characteristics of earthquakes, including their location and magnitude, contributing to earthquake preparedness and research in geology.