Researchers drilled two holes 2.5 kilometers deep into the ice at the South Pole using hot water jets.[2] They placed two highly sensitive seismometers in these holes, which will detect earthquakes with a magnitude above 5 all over the world.[2] The South Pole is the quietest place on Earth because it is cold, far from oceans, without human infrastructure, and without the influence of the Earth's rotation on seismic waves.[2] Noise from ocean waves, wind, weather or human activity does not exist here, which enables accurate measurements.[2] Seismometers were manufactured by the Canadian company Nanometrics with the lowest self-noise level in the world.[2] The previous seismometer from 2002 at a depth of 300 meters was aging, so it was replaced.[2] The sensors are already functional, communicating and tilted within 1.5 degrees from vertical; within a month they are completely frozen.[2] They experience absolute silence during the polar winter.[2]