What are icequakes?

The interior of Antarctica has icequakes which, although they are much smaller, are more frequent than earthquakes in Antarctica. The icequakes are similar to earthquakes, but occur within the ice sheet itself instead of the land underneath the ice. Polar observers detect icequakes using South Pole seismometers, located 1,000 feet (304 meters) beneath the surface of the 10,000-foot-tall (3,048-meter-tall) ice cap. These seismometers measure and record the quietest vibrations of Earth.