Citizen science at heart of new study showing COVID-19 seismic noise reduction

Raspberry Shake

IMAGE: Locations of the 268 global seismic stations used in the study. Lockdown effects are observed (red) at 185 of 268 stations. Symbol size is scaled by the inverse of population… view more  Credit: Reprinted with permission from T. Lecocq et al., Science 10.1126/science.abd2438 (2020).

Research published in the journal Science, using a mix of professional and Raspberry Shake citizen seismic data, finds that lockdown measures to slow the spread of the virus COVID-19 reduced seismic noise by 50% worldwide.

By analyzing months-to-years long datasets from over 300 seismic stations in 78 countries, including 65 Raspberry Shake seismographs, the report was able to demonstrate that ambient seismic noise levels were reduced in many countries and regions around the world, making it possible to visualize the resulting “wave” starting in China, then moving to Italy and the rest of the world. This seismic noise reduction represents the total effects of physical / social distancing measures, reduced economic and industrial activity, and drops in tourism and travel. The 2020 seismic noise quiet period is the longest and most prominent global anthropogenic seismic noise reduction on record.

The study was spawned after the lead author, Dr. Thomas Lecocq, decided that the best way to tackle the problem of analyzing data from all around the globe was to share his method with the seismological community. This started a unique collaboration involving 76 authors from 66 institutions in 27 countries. The study’s lead authors are based in Belgium, the United Kingdom, New Zealand and Mexico.

Seismometers are sensitive scientific instruments to record vibrations traveling through the ground – known as seismic waves. Traditionally, seismology focuses on measuring seismic waves arising after earthquakes. Seismic records from natural sources however are contaminated by high-frequency vibrations (“buzz”) from humans at the surface – walking around, driving cars, and getting the train all create unique seismic signatures in the subsurface. Heavy industry and construction work also generate seismic waves that are recorded on seismometers.

There are many thousands of seismic monitoring stations around the world, and it took a team effort to download, process, and analyze the many terabytes of data available. Data came from high-end seismic monitoring networks, as well as Raspberry Shake citizen seismic sensors, sharing data to a global community. Raspberry Shake operates the largest singular network of real-time seismographs in the world, which are used in various applications including research, professional vibration monitoring, and by hobbyists. The research involved major collaboration between academic and citizen scientists using this network.

“This is a great example of the type of role citizen seismology can play in contributing to the scientific record,” Raspberry Shake chief scientist Ian Nesbitt said in a statement. “We are very proud of our community’s involvement in this unique study.”

While 2020 has not seen a reduction in earthquakes, the drop in the anthropogenic “buzz” has been unprecedented. The strongest seismic noise reductions were found in urban areas, but the study also found signatures of the lockdown on sensors buried hundreds of meters into the ground and in more remote areas, such as in Sub-Saharan Africa.

The study found a strong match between seismic noise reductions and human mobility datasets drawn from mapping apps on mobile phones and made publicly available by Google and Apple. This correlation allows open seismic data to be used as a broad proxy for tracking human activity in near-real-time, and to understand the effects of pandemic lockdowns and recoveries without impinging on potential privacy issues.

The environmental effects of the pandemic lockdowns are wide and varied, including reduced emissions in the atmosphere and reduced traffic and noise pollution impacting wildlife. This period of time has been coined “anthropause”. This new study is the first global study of the impact of the anthropause on the solid Earth beneath our feet.

Will the 2020 seismic noise quiet period allow new types of signals to be detected? The study has shown the first evidence that previously concealed earthquake signals, especially during daytime, appeared much clearer on seismic sensors in urban areas during lockdown. The study’s authors hope that their work will spawn further research on the seismic effects of lockdown. Finding previously hidden signals from earthquakes and volcanoes will be one key aim.

With growing urbanization and increasing populations globally, more people will be living in geologically hazardous areas. Therefore it will become more important than ever–especially with the rising popularity of citizen seismology–to characterize the anthropogenic noise humans cause so that seismologists can better listen to the Earth, especially in cities, and monitor the ground movements beneath our feet.

Full details of the study can be found in the report.

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Patrick MJD
July 25, 2020 2:43 am

Yes I can believe that. Here in Sydney, Australia, it’s getting busier. I actually enjoyed the lockdown period while I was working through it. Roads were empty, shops closed or empty, trains empty. Now it is returning to some sort of normality. But there is a certain increase in rudeness.

July 25, 2020 3:10 am

The quiet peace was nice while it lasted. But the economic fallout will be devastating. And it didn’t affect global CO 2 levels at all. It’s not emissions, it’s a natural recovery from the LIA.

Ed Zuiderwijk
Reply to  Chaswarnertoo
July 25, 2020 3:42 am

I think you will find that the CO2 production of China did not drop nearly as much as it should to have a noticeable effect globally.

Ron Long
Reply to  Ed Zuiderwijk
July 25, 2020 7:41 am

In that case, Ed, forget about it!

Ron Long
July 25, 2020 3:12 am

Interesting post. I like the idea of utilizing a relatively quiet period to analyze the more subtle natural vibrations. However, considering the Inverse Square aspect of Newton’s Gravity Law, I’m guessing that remote seismic stations cannot detect anthropogenic tremors at all. Raspberry Shake? Rasping sound? What?

Bruce Cobb
July 25, 2020 5:30 am

That is terrific news. Now, without all that background noise we will certainly be able to hear the Arctic SCREAMING. In fact, I can hear it now. Wait, no, that’s my wife yelling at me to MOW THE LAWN!
Just kidding. Though that grass is getting mighty tall.

Loren C. Wilson
July 25, 2020 5:33 am

The research-quality instruments used to be well-sited but many are located at universities in big towns. The same urban area that leads to heat island effects also leads to more seismic noise. The amateur instruments may also suffer from siting issues. Hopefully the authors considered this when selecting their stations. One could cherry-pick either way to show a significant effect or none at all.

July 25, 2020 7:24 am

Neat, another area of science that amateurs can contribute useful observations. I need to get a Raspberry Shake unit for my back yard.

D. J. Hawkins
Reply to  Alan
July 25, 2020 9:58 am

It’s not a casual purchase, not at my income level anyway. Prices range from $375 to $1,500 depending on model and options. On the other hand, a university geology department could probably get a grant for a hundred or so with little effort.

Reply to  D. J. Hawkins
July 25, 2020 12:22 pm
Kevin kilty
July 25, 2020 7:40 am

I am a skeptic by nature, but I think this work is a crock. What is its purpose? To illustrate what anyone would have guessed at pretty accurately anyway? Does anyone think this reduction in noise was a good thing? It is a global economy being suffocated. Is it advocating some sort of trade-off of new science against wealth?

Humanity and a modern economy are noisy. Transport vehicles are a constant source, but why even bother to talk about sports stadiums? Have they become an interference in the progress of science? They are an occasional, and insignificant source of noise. A bigger source is blasting in mines and quarries and construction — also occasional, but scheduled. Civilization has crept in upon seismic stations, just as it has radio and optical astronomy. Put your instruments in better places, or convince the local populace to modify their behavior.

Ah, but toward the end of the paper we note that many of the applications mentioned are monitoring human mobility — one of the great bugaboos of our new religion.

What does a 50% reduction in noise mean? In London would it mean going from a din over which a tourist cannot hear the Westminster chime to a one-half din over which a tourist still cannot hear the chime? Could it get any quieter in the mountains of the interior Mountain West?

Maybe I am just crabby today, but this seems like poor science to me. And look at that list of authors! It’s like something right out of CERN.

Ed Bo
Reply to  Kevin kilty
July 25, 2020 11:09 am

Kevin – The “seismic noise” they refer to is ground vibration, not acoustic noise.

Kevin kilty
Reply to  Ed Bo
July 25, 2020 1:02 pm

If you read the report they are also speaking of acoustic noise being correlated to the seismic noise, but I was simply drawing an analogy.

Gordon A. Dressler
July 25, 2020 8:15 am

Finally . . . a long sought explanation for the phrase “What’s all the buzz about?”

Thank you.

Reply to  Gordon A. Dressler
July 25, 2020 10:33 am

So authors found no “earth-shattering” noise even under Portland, US of A?

Tom Abbott
Reply to  gringojay
July 25, 2020 5:00 pm

They couldn’t hear all those fireworks going off in Portland, or all the gunshots in Chicago and New York City? They can’t hear all those Muslims in China crying?

Ed Bo
July 25, 2020 11:08 am

I am a member of the “precision engineering” community, where we often want to control down to the nanometer, and even sub-nanometer level. This is for fields like semiconductor fabrication and precision optics.

At these levels, ambient vibration is a big problem. When I want to do experiments without specialized isolation stages, I will go into the lab at 5am, before there is traffic and before the HVAC system comes on.

I have closely followed the engineering of the LIGO gravity wave detectors. One of the biggest challenges has been isolating the detectors from ambient vibration, especially seismic noise. This noise dwarfs the gravity wave effect they are looking for.

Even though these detectors are well inland, they have a particular challenge in rejecting the vibration from ocean waves crashing on the shore every 6 or 7 seconds (typically). At one of the detectors, nearby operation of lawn mowers was an unexpected problem.

July 25, 2020 12:30 pm

Humans are interested in all sorts of odd things — like “How much is the land under me “shaking” today?”

Errors occur when researchers try to add “meaning” to the data.

In my area, the passing of trains and trucks would produce most of the seismic data — obscuring the motions of the Hudson River fault nearby.

July 25, 2020 7:29 pm

Seems to me that there must be a prominent diurnal signature in anthro-seismic noise.

July 25, 2020 7:51 pm

“With growing urbanization and increasing populations globally, more people will be living in geologically hazardous areas.”
Assuming surface and shallow sub-surface disturbances have a relationship to the detection or generation of deep sub-surface activity, then maybe. Perhaps it is useful to re-calibrate a noise baseline. But significant geological events are detected directional from sensors located at great depth. It is difficult to imagine how this would seriously help prevent damage or loss of life or property.
On the other hand, it will be really useful to economists when they attempt to gauge the effect of pandemic mitigation on economies, or for intelligence analysts to begin to pin down when activity actually started to change in e.g. China.

Gordon A. Dressler
July 26, 2020 9:59 am

Speaking of “earth-shattering” noise, I have it on good authority that the US Department of Defense was once very concerned about Red China’s secret weapon to destroy a large part of the western hemisphere in event of all out war between the two countries.

To wit: China would pre-distribute to its over 1 billion citizens (at the time) well-synchronized, cheap, high-stability (i.e., quartz oscillator) watches. In event of outbreak of war with the West, Chinese radio would broadcast via national radio and TV the exact time that all of its citizens were to jump as high into the air a possible. The double impulse of this much mass nearly-simultaneously pushing off from, and then a second or so later hitting, the Earth’s surface would cause a global shock wave that would a short time later be concentrated at the antipode from China, in Argentina near Buenos Aires, and in turn this would be sufficient to set off massive earthquakes throughout South and North America, especially along the San Andreas fault in California and the New Madrid fault in the Midwest USA.

I am nor privy to the countermeasures the US DoD must surely have developed against this threat. Perhaps a EMP satellite specifically designed to disable quartz watches?

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