The seismic noise level has dropped by as much as 50 per cent between March and May due to lockdowns this year, according to researchers.
Ever heard of space-based monitoring of seismic activities? This topic creates a scope for potential prelims question…
What is Seismic Noise?
- Seismic noise refers to vibrations within the Earth, which are triggered by natural and man-made phenomena like earthquakes, volcanoes and bombs.
- Seismometers, specialised devices that record ground motions, also capture seismic noise.
- Everyday human activity — such as road traffic, manufacturing in factories, the sound produced by planes roaring overhead, or simply people walking down the street.
- The sound signals created by human beings are often referred to as anthropogenic seismic noise.
- Seismic noise acts almost like background sound for seismologists — it is the unwanted component of signals recorded by a seismometer.
Variations in noise levels
- The level of anthropogenic seismic noise recorded varies based on a number of factors.
- Highly-populated urban areas will generate more vibrations from human activity than less densely populated regions.
- Timing too plays an important role. The degree of seismic noise is found to be much lower during public holidays.
Why is this important to record this noise?
- Due to this, scientists will be able to spot weaker signals.
- Such small signals tell us about a geological fault making seismic hazard assessment more accurate.
- This means that scientists will have a better shot at monitoring a whole range of seismogenic behaviour, including the smallest earthquakes or the early signs of a volcanic eruption.
