Best time to study soil, seismic activity
› If lockdowns continue in the coming months, city-based detectors around the world might be better than usual at detecting the locations of earthquake aftershocks
ANDY FRASSETTO, seismologist
NEWDELHI: This is possibly the best time to monitor and study seismic events like the detection of small earthquakes as many parts of the world are in lockdown. The transient seismic “noise” from vehicles, trains, metros, construction work etc which used to mask the sound of seismic activity beneath the soil is now reduced greatly, according to analysis by seismologists.
The Royal Observatory of Belgium tweeted on March 20: “The earth continues shaking. Ground movements at frequencies 1-20 Hz, mainly due to human activity (cars, trains, industries,...) are much lower since the implementation of the containment measures by the government.” Thomas Lecocq, a seismologist from the Royal Observatory of Belgium, who is studying the changes in seismic noise due to the lockdown, tweeted on March 27 that mean noise level was 33% lower since stay-at-home orders were issued in Belgium.
“This is probably the best time for scientists like me to study soil structure and natural waves because there is little transient noise being recorded by our monitors...,” said AP Pandey, seismologist at National Centre for Seismology under the Ministry of Earth Sciences. But India has not analysed seismic noise reduction because of the lockdown yet.
Nature journal reported on the observations of seismologists on Tuesday. “If lockdowns continue in the coming months, city-based detectors around the world might be better than usual at detecting the locations of earthquake aftershocks,” Andy Frassetto, a seismologist at the Incorporated Research Institutions for Seismology in Washington DC was quoted as saying in the report by Nature.
Stephen Hicks, Faculty of Engineering, Department of Earth Science & Engineering at the Imperial College, London, also tweeted on March 27 about how a seismometer saw the UK lockdown. Data from the British Geological Survey’s station suggests a reduction in average daytime background seismic noise because of much reduced traffic on roads. There are similar tweets from seismologists in other parts of the world.