COVID-19 lockdowns dramatically reduced seismic noise from humans
Widespread global lockdowns resulting from the COVID-19 pandemic reduced the amount of seismic noise produced by humans by up to 50 percent in some places, a new study finds. This 2020 seismic noise quiet period began in late January and hit its peak from March to May. It was the longest and most prominent reduction of seismic waves from human activities in recorded history, researchers report online July 23 in Science. Around the world, seismometers don’t just pick up loud echoes of earthquakes rumbling through the subsurface. The instruments also detect many subtle reverberations, such as the hum caused by ocean swells or groundwater circulating underground, as well as the periodic tremors that sometimes signal an impending volcanic eruption (SN: 9/29/04; SN: 6/18/20; SN: 5/14/20). Seismometers can even detect ground vibrations generated by everyday human activities, such as traffic, construction and parades or football games. The link between seismic vibrations and noise from...