Background noise and less seismic activity caused by humans during COVID-19

Measuring seismic activity often requires locating instruments away from population centers. During COVID-19, the seismic activity caused by humans dropped a lot:

architecture bedrock bridge building

Photo by George Becker on Pexels.com

Writing today in the journal Science, dozens of researchers from around the world show that the seismic activity from our civilization plummeted as lockdowns went into effect. This “anthropogenic seismic noise,” as seismologists call it, comes from all manner of human activities, whether that’s running factories, operating cars or trains, or even holding concerts. Seismometers pick up these activities as a kind of constant din, which actually peaks on weekdays, when more people are moving around, and falls on weekends when economies slow down. All this activity that seismometers detect mixes with the natural rumbles that scientists are really interested in, like earthquakes, volcanoes, and landslides.

But boy, are they interested in the anthropogenic seismic noise now—or the lack thereof, as humans began to shelter in place. “We see it effectively moving around the globe as a seismic lockdown wave,” says Royal Holloway University of London seismologist Paula Koelemeijer, one of the paper’s coauthors. “So starting in China originally, then in different places in Italy, and then going through Europe. And whenever lockdowns happened in different countries, we see the effect that’s up to an 80 percent reduction in the amplitude of the seismic noise in some places.” The average was about 50 percent…

Normally, seismologists don’t bother monitoring urban environments for just this reason: There’s way too much noise muddying the signals of Earth’s natural processes. But for the past few years, citizen scientists have been collecting signals thanks to a clever little device called the Raspberry Shake, a Raspberry Pi computer outfitted with sensors to create an internet-connected seismometer. “Those instruments have been popping up more and more in people’s homes,” says Koelemeijer. “And so about 40 percent of our data stations that we looked at have been these citizen science instruments. It’s just people finding it funny, geeky, to have one of them. Like, I’m one of those people. I have one in my house.”…

But it was in a remote part of Germany where seismologists recorded perhaps the most surprising lockdown data. The Black Forest Observatory is not only isolated, and thus considered to be a reference low-noise laboratory, but its instruments are stowed over 150 meters below the surface, in bedrock. Yet they, too, picked up a small noise reduction at night during the lockdown. “Germany was a big surprise for us, because that station is very much a remote station, and seen as a very good seismic station for looking at natural signals,” says Koelemeijer. “So the fact that we saw it there was quite remarkable.”

Human activity influences all sorts of spheres that we do not often consider. Here, humans create a lot of noise and activity below the surface of the earth. There are occasionally complaints about noise pollution but most people put up with a certain amount of noise and vibrations in the places where they live.

This reminds of several different aspects of working with “background noise.” Working in radio, I often used sound effects for promotional material. The sound effect CDs we had contained a variety of background noise or din. For example, the city options largely contained traffic noise with vehicle rumbling and honking mixed together.

More recently, sports broadcasts have adjusted to teams playing in stadiums with no fans present in the stands. They often use recordings of fans where a sound technician has the ability to respond to play on the field (such as cheering for a good play for the home team or a negative response from fans). Without such background noise, the broadcast sounds very different: voices echo, the players can be heard, and a comforting or familiar element of the broadcast is lost.

All together, the background noise of our lives matters in everyday activity and in scientific measurement. If COVID-19 changes human movement and interactions, what we hear by ear and scientific instruments also changes.

Home all day, hear the noise of daily work around your residence

With more people at home during the day, they can hear more of what goes on during a typical day. And they may not like it:

Cities, towns and villages in New York, New Jersey and elsewhere in the country have created bans or sought voluntary cuts in the use of leaf blowers in suburban neighborhoods. Town leaders noted that with everyone sheltering in home, the constant din was an added nuisance…

The municipal actions are a departure in the ongoing saga of leaf blowers, one marked, in many towns, by equal parts irritation and inaction. Everyone hates hearing them down the block, but no one complains about the swift and eye-pleasing work they accomplish on their own lawns. And so a silent majority has carried on, under the whine of the motor.

Some residents have apparently questioned whether the machines could be spreading the coronavirus. The village of Croton-on-Hudson, N.Y. raised the same worry on Twitter this week…

In Westfield, N.J., Mayor Shelley Brindle, in a statement, asked homeowners and landscapers to keep the blowers locked away until at least noon ever day.

This comes amid broader discussions about banning gas leaf blowers and other gas-powered outdoor equipment. Compared to electric or battery-powered equipment, they produce more noise and exhaust. This could be an interesting time to nudge people toward different equipment – in the name of noise, environmental concerns – though asking them to do so in the midst of a crisis will make it more difficult.

I wonder how much the perception of the noise problem is also due to the time of year. I wrote two years ago about common summer noises that can interrupt tranquility: air conditioners, lawnmowers, construction, etc. Once the weather starts warming up, more people are outside and more people are doing work outside. The person in one house who wants to sit on their deck and enjoy some peace and quiet competes with the person next door who enjoys keeping their yard neat and green. And both of them may dislike the municipal road project that reconstructs the next street over and produces noise for weeks. If the COVID-19 induced lockdown started in November, would people have the same noises to complain about?

At the same time, dealing with noise is tricky among neighbors and within a community. People generally know that certain locations are noisier than others and adjust accordingly. Some people even live right under runway paths. Businesses also have a stake in this; as is noted at the end of the article cited above, not using certain yard equipment is possible but raking and pruning by hand will take more time and cost more money. Keeping everyone happy regarding noise is likely to be difficult.

Living in the shadow of Heathrow and other major airports

A reporter travels to a neighborhood just next to the runways at Heathrow Airport and tries to understand how people live there:

It’s a nice perk, if you don’t mind the to and fro of planes overhead—one taking off or landing every 45 seconds, every day, every year. They soar within a few hundred feet of the rooftops, blocking the sky like giant aluminum birds. And they make a helluva racket too. “It’s almost deafening if you’re standing underneath,” says Bertie Taylor, who photographed Myrtle Avenue for his series Under the Flight Path.

Feltham has been a transportation hub since the early 20th century, when it hosted Britain’s second largest railway yard, targeted by German air strikes during World War II. But it didn’t become the consistently noisy place it is today until January 1, 1946, when an Avro 691 Lancastrian departed Heathrow for Argentina, marking the airport’s first flight. In the 1960s, its two main runways—one located just a quarter-mile northwest of Myrtle Avenue—were extended a few thousand feet to service even bigger planes like the Boeing 747.

Noise levels are allowed to reach up to 94 decibels during the day (equivalent to a jackhammer 50 feet away) and 87 decibels at night (a gas-powered lawn mower)—though they’ve fallen in recent decades with quieter engines and smarter flight paths. Still, last year Heathrow received an average of one noise complaint every seven minutes. Noise isn’t the only nuisance. Nearby communities also receive an extra dose of air pollution from vehicle and aircraft traffic, not to mention the occasional scare: In 2008, a Boeing 777 nearly slammed into Myrtle Avenue after its engines failed.

All this sounds nightmarish—and indeed, it troubles locals. But when Taylor visited Myrtle Avenue in September 2018, curious to see what life near an airport is like, folks seemed more irritated by having their driveways blocked in by planespotters’ cars. Aviation enthusiasts from as far as Germany and the Netherlands throng to the green park near the airport fence to ooh and aah at landing Airbus 380s and Boeing 777s. One middle-aged man even stood atop his van in a nearby field, livestreaming the spectacle on Facebook.

Humans can live in all sorts of conditions, including regular noise and visitors. So what would motivate these residents to stay in this location? A few hypotheses:

1. Housing is cheaper here. The noise would bother a lot of potential homeowners so a dwelling that might be more expensive elsewhere (and this is the expensive London region after all) might be less expensive.

2. Proximity to jobs, particularly in the transportation sector. For people with jobs at Heathrow or in something connected to the air industry, this could be a convenient location.

3. They grew up in this area or have long-term connections to the industries (railways, flying) in the community.

On the other hand, perhaps some of the residents do leave when one of these factors that once pushed them to stay becomes less important. With some personal experience living near a busy railroad line, I know people can get used to noise and rumbling but wouldn’t the average resident leave when they could?

Since airports are not usually too far from dwellings these days (they might have been in previous decades but many metropolitan regions have expanded), someone has to live near the airport. Maybe even some come to like it. But, living that close with the noise and the shadows is a different experience many homeowners would look to avoid.

The demise of gas-powered leaf blowers

One tool in the arsenal of those who care about lawns (i.e. many Americans) may be on the way out due to pollution and noise. See this brief overview of how Washington, D.C. will soon be free of gas-powered leaf blowers:

Back in the fall of 2015, in the first installment in this series, I mentioned that a group of community activists in our hometown of Washington, D.C., had begun an effort to get noisy, hyper-polluting, gas-powered leaf blowers banned in the capital, as has already happened in more than 100 cities across the country.

The reasons for the ban are: the obsolescence of the technology, which is orders of magnitude more polluting than other machines and engines now in common use; the public-health danger, above all to hired work crews, of both the emissions and the damagingly loud noise from the gas blowers; and the rapid advent of battery-powered alternatives, which are quieter and dramatically less polluting.

The purpose of this post is to record how the story turned out:

  • From 2015 to early 2018, more than one-third of all the Advisory Neighborhood Commissions in the District, elected bodies covering seven of the eight wards in the District, voted to endorse this mandatory shift.
  • In July 2018, the council had hearings on a phaseout measure, sponsored by the council member Mary Cheh.
  • Late in the year, the 13-member council passed Mary Cheh’s bill, unanimously.
  • D.C. Mayor Muriel Bowser then signed the bill, and it will take effect as of January 1, 2022.

The pollution aspects of these tools is little-known. The gas powered devices that are used around the yard and home can generate significant amounts of pollution. As Fallows points out in his longer piece on this topic in the April 2019 print edition of The Atlantic, significant advancements have been made in reducing pollution in other devices but two-stroke engines pollute a lot.

The noise dimension is also worth paying more attention to. Suburban communities, home to many leaf blowers, can be noisy places during the summer months. Those who actually use the leaf blowers can have more direct negative consequences.

While the solution to these problems seems to be battery operated or electric tools, I wonder if homeowners and business owners could advance to a point where grass clippings on sidewalks and driveways or leaves do not always need to be removed. Is it a huge problem that there is some grass left over on the sidewalk? Could leaves be left to naturally break down? This would require a significant shift in thinking about lawns as pristine showpieces and “nature.”

The never-ending summer hum of lawn mowers, construction, ACs, pressure washers, and more

As soon as the weather started turning warmer, the summer drone began. Not crickets or the sounds of children playing baseball or swimming at the pool. Rather, it was the background noise of summer that seems unavoidable for months: in a suburban subdivision with numerous nearby subdivisions, there is always someone within a relatively short distance using a lawnmower, a weedwacker, a pressure washer, or construction equipment. The noise starts as early as 7:30 AM and stops around 8 PM.

The typical idyllic summer looks something like this with green lawns, sunshine, and peaceful looking homes:

Lawn

But, this image fails to include the background noise that is ever present. That noise is often less than idyllic, particularly if it is close and/or persistent.

I know the expectation of having quiet is one that is not possible in many settings, particularly in urban areas. Many American residents have little exposure to true quiet (and may even find it unnerving). But, the early suburban ideal of the mid 1800s was to help urban residents get back to nature (or an altered environment that fit certain standards of “nature). That quiet of nature – rustling trees, bird calls, insects, stillness – is simply not possible in most suburban settings today either. Some of this is due to location and the need to locate near major roads or other land uses (such as commercial or industrial properties). Some is due to the rise of air conditioning which made development possible in certain climates. Yet, it also comes from all the maintenance required for single-family homes and their environment. Home upkeep to typical standards, such as a good looking lawn, is aided by noisy tools.

I thought recently about having noise free days in suburban neighborhoods. Could everyone in a certain portion of a community schedule their outdoor maintenance for two or three days a week? This would make it more difficult to schedule things but the trade-off could be less noise for everyone. This could work with homeowner’s associations since they already contract for regular lawn service that typically happens on the same day each week. Imagine residents could have at least one weekday in which they knew the only noise outside would be from vehicles – would it be a better experience?

Rumbler emergency siren to shake your vehicle

Milwaukee police are trying out a new kind of siren:

It’s a siren you don’t just see, and hear, you actually feel it. It’s called the Rumbler and it’s expanding on a police force near you. It’s a siren that emits a low frequency sound that vibrates your car. It goes through the material of the vehicle, the frame, and seats. The subwoofer is located inside the grill of the car. Milwaukee K-9 Police Officer, Jeff Lepianka says the department has been adding the sirens over the last few years to battle distracted driving.

Lepianka says, “Drivers will have their ear buds in, be on their cell phone. This siren will break through this and get the people to pull over so I can get to where we need to go.”…

“With the Rumbler going people 10 to 15 car lengths are already getting to the side.”

Those precious minutes saved, could save lives.

In the name of safety and combating distracted driving, perhaps this is the wave of the future. This possible technology prompts two thoughts:

  1. This reminds me of the use of high-frequency sound devices used to chase away teenagers. Since adults lose the ability to hear such frequencies as they age, it can be particularly effective in targeting loitering youngsters.
  2. When we eventually all have self-driving cars, it would be easy to automatically pull all vehicles aside to allow emergency vehicles through. This could certainly help decrease response times but it would certainly be odd – at least the first time or two – to be automatically sidelined.

The article suggests pulling over is often delayed because of distracted driving but I wonder if this is also the case even when the drivers aren’t engaged in other activities. Have driving norms changed? At what distance are drivers supposed to pull over? I’ve noticed that fewer emergency sirens use their sirens and it is not always easy to see flashing lights.

A reporter spends the night under O’Hare’s new air traffic patterns – and doesn’t report much

After recently learning of an uptick in complaints regarding airplane noise around O’Hare Airport, one reporter spends the night in an affected neighborhood:

On the horizon are five blinking lights, all destined for the runway that parallels Thorndale Avenue, which now handles almost half of overnight arrivals. A little south, coming in toward the Lawrence Avenue runway, are two more jets. As they converge overhead, it looks as if the Northwest Side were in the midst of an alien invasion.

At one point, the planes coming in pass overhead at the same time, and the whines of the engines bounce off each other in stereo. JP launches the noise monitor app on his phone and registers 86 decibels, which, according to the Illinois Deaf and Hard of Hearing Commission, is roughly equal to the sound of a screaming child. The FAA claims the metric for “significant” jet noise—meaning the amount at which homeowners can be eligible for soundproofing subsidies—is a day-night sound level average of 65 decibels. But only those residences within the FAA’s noise contour map (Sauganash Woods and most other Northwest Side neighborhoods are not) qualify for the soundproofing…

Evening settles in, and JP and I sit in his family room to watch the Bears-Packers game. Every once in a while, a plane whizzes by, which actually provides a welcome distraction from the historic pummeling the Packers are giving the Bears. After the game, my hosts head to bed, and I try to get some sleep on the couch.

A few minutes later, around 11, the jets start rumbling by again, often in 30-second intervals. Using radar and tracking apps on my iPhone, I watch the dots as they approach: At 11:55, a Boeing 747 Yangtze River Express from Shanghai blows in at 1,300 feet. At 11:56, an Airbus from Phoenix roars over the house. The last plane I see on the screen before dozing off at 12:30 a.m. is a Cessna coming in from Green Bay. (Jay Cutler’s private jet?)

The general theme of the report is that some people’s lives are affected by these changes at O’Hare. At most, it suggests at least a few families, businesses, and communities are affected. But, we don’t hear if life is unbearable. We don’t hear if everyone in these neighborhoods and communities feels the same way. We don’t get a broader view from elsewhere in the region. We get a narrow slice of life with an uncertain conclusion.

Articles like these tend to draw my sociological attention because this one addresses (a) an area experiencing some significant change, which leads to differing reactions from people and (b) the issues at O’Hare represent an opportunity to discuss metropolitan-wide issues. Certainly, other areas in the country have similar issues, whether it is from airport noise or an undesirable facility nearby or because the powers that be decided to change things for the good of the majority. This particular case at O’Hare could provide an interesting comparison to see exactly how this balance between individuals, communities, and the region plays out. Yet, most of the media coverage I’ve seen so far tends to focus on individual complaints or relatively small communities.

When a few people generate most of the complaints about a public nuisance

The newest runway at O’Hare Airport has generated more noise complaints than ever. However, a good portion of the complaints come from a small number of people.

She now ranks among the area’s most prolific complainers and is one of 11 people responsible for 44 percent of the noise complaints leveled in August, according to the city’s Department of Aviation.

The city, which operates the airport, pokes at her serial reporting in its monthly report by isolating the number of complaints from a single address in various towns. It’s a move meant to downplay the significant surge in noise complaints since the airport’s fourth east-west runway opened last fall, but it only seems to energize Morong…

Chicago tallied 138,106 complaints during the first eight months of the year, according to the Department of Aviation. That figure surpassed the total number of noise complaints from 2007 to 2013.

The city, however, literally puts an asterisk next to this year’s numbers in monthly reports and notes that a few addresses are responsible for thousands of complaints. The August report, for example, states that 11 addresses were responsible for more than 13,000 complaints during that 31-day period…

But even excluding the serial reporters, the city still logged about 16,000 complaints in August, about eight times the number it received in August 2013.

There are two trends going on here:

1. The overall number of complaints is still up, even without the more serial complainers. This could mean several things: there are more people now affected by noise, a wider range of people are complaining, and/or this system of filing complaints online has caught on.

2. A lot of the complaints are generated by outliers, including the main woman in the story who peaked one day at 600 complaints. It is interesting that the City of Chicago has taken to pointing this out, probably in an attempt to

This is not an easy issue to solve. The runway issues and O’Hare’s path to being the world’s busiest airport again mean that there is more flight traffic and more noise. This is not desirable for some residents who feel like they are not heard. Yet, it is probably good for the whole region as Chicago tries to build on its transportation advantages. What might the residents accept as “being heard”? Changing whole traffic patterns or efforts at limiting the sound? Balancing local and regional interests is often very difficult but I don’t see how this is going to get much better for the residents.

“How Trains Can Be Silent Killers”

Over 780 people were killed by trains last year in the United States and it is possible for them to sneak up quietly on people:

“Statistically, every 94 minutes something or someone is getting hit by a train in the United States,” says David Rangel, deputy director of Modoc Railroad, a training school for future train engineers. Now, most of those incidents don’t involve people—Rangel’s statistic also includes the occasional abandoned shopping cart, wayward livestock, and other objects that somehow find their way onto the tracks. But, according to the Federal Railroad Administration (FRA), 784 people were killed in train-related accidents in 2013, the highest total in the last four years.

That accident rate comes down to a combination of factors, each increasing the likelihood of disasters. “Railcars are incredibly quiet,” Rangel says. “[Tracks] are designed to achieve the lowest possible coefficient of friction…At age 62, I could push a train car down a track.” Unlike a steam engine that would hammer the rails (a main reason why they were retired), modern railcars glide with low friction, and crushed rock underneath the tracks helps diminish impact. “You won’t hear it or feel it,” Rangel says.

The Doppler Effect, which explains how sound changes pitch based on an observer’s location relative to the sound’s origin (the reason sirens sound different as they approach you), plays a role. However, since they were in front of the train, where the pitch would be higher, they’d be more likely to hear the siren and doesn’t explain why they didn’t hear the train coming. Unsurprisingly, some train-collision victims often were wearing headphones or earbuds at the time. (These two were not wearing headphones.)

Terrain can also add to the danger. If a locomotive passes through a corridor lined with trees, those trees act like sound baffles in a recording studio, Rangel says, suppressing the noise. The average railcar traveling at 50 mph measures in decibels between at “loud voice” and a “shout,” according to the FRA. The horn itself, though, can be even louder than sirens on an ambulance.

When you think about it, it is surprising how open train tracks are to the general public. The average city or suburban dweller could probably get to a railroad line easily and walk around. This also includes a large number of at-grade crossings, a particular problem in the Chicago region with lots of freight traffic and lots of people. But, the goal of railroad lines is not to minimize accidents but rather to transport goods and people as efficiently as possible.

h/t Instapundit

Diamond grinding to reduce highway noise

One Lake County community is paying out of its own pocket to reduce noise on I-294 by diamond grinding the road:

The village [of Green Oak] will pay nearly $338,000 for a process called diamond grinding to hopefully reduce the racket along that stretch of road.

“The idea here was to grind it and produce a quieter pavement and pavement noise in the lower frequency range so it wasn’t so obnoxious,” Village Engineer Bill Rickert said.

That sound also described as “singing” by Rickert spurred several complaints after the tollway widening was completed about three years ago, and sent village leaders on a quest for a solution…

In the simplest terms, the concrete road surface had been tined or grooved perpendicular to the road surface, he said. The diamond grinding changed the grooves to run parallel, evoking “more of a corduroy-type feel,” and theoretically producing lower noise levels in frequencies less noticeable to the human ear.

While diamond grinding emerged as the village’s proposed solution, it isn’t used by the tollway as a noise reducing technique.

It would be interesting to see how this solution compares with building sound barriers – is diamond grinding cheaper or more effective? If this is an effective technique and people agree about this, why doesn’t the Tollway use it?

I have had some more interest in this lately because our neighborhood borders a busy arterial road that is being expanded from 2 to 4 lanes. Because of this, sound barriers have been installed. I don’t think they look too bad with a sort of faux beige brick look. Granted, I don’t live in a house that backs up to these walls and I assume there is a price (in housing value) to pay for backing up to these walls. Going further, at night we can faintly hear the nearby highway that is 1.5 miles away – it is a sort of background noise. But having grown up close to a railroad track which produced more sporadic but louder noise, can’t you simply get used to these things? Perhaps the difference here is that people in these neighborhoods near the Tri-State haven’t had this level of noise until the highway was expanded.