The planet is making a lot less noise during lockdown.
- A team of researchers found that Earth's vibrations were down 50 percent between March and May.
- This is the quietest period of human-generated seismic noise in recorded history.
- The researchers believe this helps distinguish between natural vibrations and human-created vibrations.
The planet's vibes are down.
That's the consensus from a team of researchers at six European institutions; the study was based at the Royal Observatory of Belgium. Their research, published in Science, found that human-linked vibrations around the planet dropped by 50 percent between March and May 2020—the quietest period of seismic noise since scientists began monitoring the Earth.
Seismometers were invented in China during the 2nd century, though today's version dates to the 1880s, when a team of British and Scottish engineers worked as foreign-government advisors in Japan. Today, we generally discuss seismic waves in terms of bombs, earthquakes, and volcanic eruptions, though human activity, such as travel and industry, also produce such waves.
As the world slowed down during the pandemic—the researchers call it an "Anthropause"—travel and industry ground to a standstill. For the first time in recorded history, researchers were able to differentiate between natural seismic waves and those caused by humans. The drop was most noticeable in densely-populated urban areas, though even seismometers buried deep in remote areas, such as the Auckland Volcanic Field in New Zealand, picked up on the change.
Dr Stephen Hicks, a co-author from Imperial College London, comments on the importance of this research:
"Our study uniquely highlights just how much human activities impact the solid Earth, and could let us see more clearly than ever what differentiates human and natural noise."
Earth is quieter as coronavirus lockdowns reduce seismic vibration
The team investigated seismic data from a global network of 268 stations spread out across 117 countries. As lockdown measures in different regions began, they tracked the drop in vibrations. Singapore and New York City recorded some of the biggest drops, though even Germany's Black Forest—famous for its association with the Brothers Grimm fairy tales—went quieter than usual.
The researchers also relied on citizen-owned seismometers in Cornwall and Boston, which recorded a 20 percent reduction from relatively quiet stretches in these college towns, such as during school holidays.
The environmental impact of lockdown has been dramatic. Indian skylines are notoriously grey. This collection of photos shows how quickly nature recovers when humans limit travel and industry. Such photographs also make you wonder why we cannot control emissions to begin with, now that we know the stakes.
Lead author, Dr Thomas Lecocq, says their research could help seismologists suss out the difference between human-created vibrations and natural vibrations, potentially resulting in longer lead times when natural disasters are set to strike.
"With increasing urbanisation and growing global populations, more people will be living in geologically hazardous areas. It will therefore become more important than ever to differentiate between natural and human-caused noise so that we can 'listen in' and better monitor the ground movements beneath our feet. This study could help to kick-start this new field of study."
Stray puppies play in an abandoned, partially-completed cooling tower inside the exclusion zone at the Chernobyl nuclear power plant on August 18, 2017 near Chornobyl, Ukraine.
Photo by Sean Gallup/Getty Images
The Earth is much stronger than us; humans are its products. In his 2007 book, "The World Without Us," Alan Weisman details just how quickly nature recovers from our insults. Chernobyl offers a real-world example, while earthquakes caused by fracking-related wastewater injection in Oklahoma are evidence of how much damage human "vibrations" cause.
Weisman's poetic homage imagines a symbiotic relationship with nature. This relationship depends on our cooperation, however. Weisman knows we aren't long for this world, nor is this world long for this universe: in just five billion years, give or take, Earth will implode. We all live on borrowed time. How we live during that time defines our character.
While he strikes a hopeful tone, Weisman knows nature will eventually have her way with us.
"After we're gone, nature's revenge for our smug, mechanized superiority arrives waterborne. It starts with wood-frame construction, the most widely used residential building technique in the developed world. It begins on the roof, probably asphalt, or slate shingle, warranted to last two or three decades—but that warranty doesn't count around the chimney, where the first leak occurs."
The play-by-play of our demise continues, though Weisman offers plenty of proactive advice. The question is, will we be able to live up to it? Sadly, nothing in modern society hints at the possibility.
The only way we seem willing to pause our relentless pursuit of "progress" is when we're forced to do so, as in the current pandemic. The results, as the team in Belgium shows, are measurable. Whether or not we heed the call to slow our impact remains to be seen. Given precedent, it's unlikely, though as Weisman concludes, one can always dream.
Scientists discover how to predict megaquakes earlier to improve warning systems.
- Earthquakes of 7+ magnitude share a particular pattern, find seismologists.
- The pored over data of over 3,000 earthquakes to spot a "slip pulse".
- The scientists advocate using real-time GPS sensor data in early warning systems.
As the 2019 California earthquakes remind us, these natural events can be quite nerve-racking and dangerous. Potential for terrible destruction is always just a tremor away. That's probably the worst thing about earthquakes – they come out of nowhere and cause the most mayhem simply because of their sheer suddenness. Predicting earthquakes would save lives and property, and a recent study hopes to accomplish just that.
Seismologists Diego Melgar and his colleague Gavin P. Hayes were at first looking for databases to simulate the magnitude 9+ Cascadia megaquake of 1700. But they ended up discovering a very peculiar pattern. They employed data collections of earthquakes going back to the early 1990s and their background in geophysics to spot a specific moment, happening 10-15 seconds into an earthquake event. That moment, derived from GPS data, can indicate a quake of magnitude 7 or larger.
The scientists used GPS information, in particular, because it caught even the smallest initial movements along a fault, showing the strongest acceleration of ground movement. The seismologists identified a pattern in the data called "a slip pulse" that happened during the transition period, when displacement between two plates was taking place. The top rate of that displacement predicted if the quake would be small or go mega, found the researchers.
How did they know they were on the right track? The scientists performed physics-heavy analysis of numerous databases of 3,000+ earthquakes to confirm their methodology. They correctly picked out all 12 quakes of 7+ magnitude from the early 1990s till now in two U.S. Geological Survey databases. They also hit upon the same pattern in European and Chinese databases, reports a University of Oregon press release.
"It was super exciting," shared Melgar. "As Gavin and I pored through the data for what were really unrelated reasons, we began to see these trends. We had a bit of a eureka moment where we, well, if what we're seeing is true, it means something about how earthquakes start."
Vehicles driving over a crack on Highway 178, near Trona. This follows a 6.4-magnitude earthquake in Ridgecrest, California on July 4, 2019.
Credit: Frederic J. Brown/Getty Images
The scientists think their research can lead to a greater amount of GPS stations to improve early warning system, especially ShakeAlert, along the West Coast. The sensors can be placed on the seafloor to counter the delay in relaying valuable quake information.
"We can do a lot with GPS stations on land along the coasts of Oregon and Washington, but it comes with a delay," Melgar explained. "As an earthquake starts, it would take some time for information about the motion of the fault to reach coastal stations. That delay would impact when a warning could be issued. People on the coast would get no warning because they are in a blind zone."
Melgar's previous work on real-time GPS data found it could give an extra 20 minutes of warning in cases of tsunamis.
Read their study in Science Advances.