Seismic Noise

  • Scientists at the British Geological Survey (BGS) have reported a change in the Earth’s seismic noise and vibrations amid the coronavirus lockdown.
  • These findings have come two weeks after seismologists at the Royal Observatory in Belgium observed a 30-50% fall in levels of seismic noise since schools and businesses were closed in mid-March (2020).

What is seismic noise?

  • Seismic noise refers to the relatively persistent vibration of the ground due to a multitude of causes.
  • This noise includes vibrations caused due to human activity, such as transport and manufacturing.
  • It is the unwanted component of signals recorded by a seismometer and makes it difficult for scientists to study seismic data that is more valuable.
  • Apart from geology, seismic noise is also studied in other fields such as oil exploration, hydrology, and earthquake engineering.

Benefits of reduction in seismic noise

  • Usually, to measure seismic activity accurately and reduce the effect of seismic noise, geologists place their detectors 100 meters below the Earth’s surface.
  • Because, the seismic noise vibrations caused by human activity are of high frequency (between 1-100 Hz), and travel through the Earth’s surface layers.
  • However, since the lockdown, researchers have said that they were able to study natural vibrations even from surface readings, owing to lesser seismic noise.
  • Due to lower noise levels, scientists are now hoping that they would be able to detect smaller earthquakes and tremors that had slipped past their instruments so far.