EARTH’S SEISMIC NOISE

▪️Why in News? 

✅Scientists at the British Geological Survey (BGS) have reported a change in the Earth’s seismic noise and vibrations amid the coronavirus lockdown. 

▪️About: 

✅ They have observed a 30-50 per cent fall in levels of ambient seismic noise since schools and businesses were closed in mid-March. 

✅ Seismologists around the world have now begun a collaborative effort to study the fall in seismic noise levels. 

▪️What is seismic noise? 

✅In geology, seismic noise refers to the relatively persistent vibration of the ground due to a multitude of causes. 

✅It is the unwanted component of signals  

recorded by a seismometer– the scientific instrument that records ground motions, such as those caused by earthquakes, volcanic eruptions, and explosions. 

✅This noise includes vibrations caused due to  

human activity, such as transport and manufacturing, 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. 

▪️How to reduce the noise levels help scientists? 

✅The seismic noise vibration caused by human activity are of high frequency (between 1-100 Hz), and travel through the Earth’s surface layers. 

✅Usually, to measure seismic activity accurately and reduce the effect of seismic noise, geologists place their detectors 100 meters below the Earth’s surface. 

✅ 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.

#revision_notes 

#geography 

#prelims