Recent findings by scientists at the British Geological Survey (BGS) reveal a change in Earth’s seismic noise and vibrations due to the coronavirus lockdown. This news arrives two weeks after seismologists at the Royal Observatory in Belgium noted a 30-50% decrease in seismic noise levels following the closure of schools and businesses in mid-March.
Understanding Seismic Noise
Seismic noise, a term used in geology (the study of rocks), refers to the continuous vibration of the earth’s ground, resulting from various sources. This includes vibrations due to human activities like transportation and manufacturing processes. The initial observation of seismic noise, everything documented on seismograms aside from earthquakes, dates back to the 19th century. It represents undesired components of signals captured by seismometers, making it challenging for scientists to examine essential seismic data. Besides geology, fields such as oil exploration, hydrology, and earthquake engineering also study seismic noise.
The Impact of Human Activity on Seismic Noise
Typically, geologists place their detectors approximately 100 meters underground to accurately measure seismic activity and minimize the effect of seismic noise. This is because seismic noise vibrations resulting from human activities are of high frequency (1-100 Hz) and traverse the earth’s surface layers.
The Effect of Lockdown on Seismic Noise Readings
Due to the global lockdown imposed during the COVID-19 pandemic, investigators have reported the feasibility of studying natural vibrations from surface readings, attributed to the corresponding decrease in seismic noise. With the reduction in noise levels, there is now an expectation among the scientific community that they might be able to detect minor earthquakes and tremors, which till date, have evaded their instruments.
Role of a Seismometer
A seismometer is a highly sensitive scientific instrument responsible for recording ground movements caused by earthquakes, volcanic eruptions, and explosions. However, due to their sensitivity levels, they also record other sources of vibrations including human activity like traffic movement, machinery operations, and even people walking nearby. This multifaceted recording capability further emphasizes the role of human activity in seismic noise production.
Implications of the Study
The current findings highlight the significant impact human activities impose on seismic noise levels. In light of the recent drop in seismic noise patterns during the lockdown, scientists now have an opportunity to detect previously undetected natural seismic phenomena. These insights could significantly contribute to our understanding of seismic activities and potentially improve strategies for earthquake predictions and responses.
Cited Source: IE
