Video | Business Headlines | Internet | Science | Scientific Ethics | Technology | Search

 

The Quiet Earth

As many daily activities came to a halt during lockdown, the Earth itself became quiet, probably quieter than it has been since humans developed the technology to listen in.

Seismologists have analysed datasets from more than 300 international seismic stations – including several located in New Zealand - and found the “buzz” of human activity, called anthropogenic noise, dropped dramatically.

They have dubbed this period the ‘anthropause’ because it’s the longest and most prominent anthropogenic noise reduction on record. It was detected not just in cities but in some of the planet’s most remote places including sub-Saharan Africa. 

In New Zealand, seismologist Dr Kasper van Wijk from the University of Auckland was busy looking at seismic data from the tragic eruption at Whakaari/While Island and wasn’t really thinking about lockdown until colleague Dr Thomas Lecocq of the Royal Observatory of Belgium got in touch. 

“I used the computer code for White Island to analyse Auckland’s seismic data, and to my surprise, within an hour I could confirm that Auckland was not only quiet above ground but also underground,” he says. 

Traditionally, measuring seismic waves is focused on detecting earthquakes and volcanic activity but because seismographs are so sensitive, they can also pick up vibrations from humans at the surface as we walk around, drive cars and catch a train. Heavy industry and construction work also generate seismic noise. 

New Zealand’s strict lockdown measures meant a lack of anthropogenic seismic noise was detected at places like Eden Park where a seismograph is buried 380m beneath the sports grounds, and even on Motutapu Island in the Hauraki Gulf. 

Because it is situated on a volcanic field, Auckland is a key focus for seismologists – there are 12 seismographs in and around the city, monitoring even the weakest signs of earthquakes or volcanic unrest. 

During lockdown the seismic signal of an earthquake in Mexico appeared clearer-than-normal as humans were confined to quarters. The project leaders, including Dr van Wijk, hope their work will help improve our ability to detect these previously hidden signals.

“One day a volcano in Auckland’s volcanic field will erupt but it will create seismic signals before that happens and this study reminds us that if humans made less noise, we would get an earlier warning,” Dr van Wijk says. 

Findings from the study are published in Science and show a 50 per cent reduction in seismic noise on seismographs around the world from early- to mid-2020. Lead authors were based in New Zealand, Belgium, the United Kingdom and Mexico and overall 76 scientists from 27 countries were involved. 

There are thousands of international seismic monitoring stations, some run by enthusiastic amateurs including students. Dr van Wijk heads the Ru Network of Seismometers in Schools programme which has seen dozens of seismographs installed in schools that, while not as powerful as professional seismic stations, detect earthquakes. At St Mary’s School in Rotorua the days of lockdown were quieter than even any day during the summer school holidays. 

The study found a strong match between seismic noise reductions and human mobility data from mapping apps on mobile phones, made 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, Dr Lecocq says. 

It is also the first evidence that previously concealed earthquake signals, especially during daytime, are much clearer on seismic sensors with reduced anthropogenic noise and the researchers hope this will help them detect previously hidden signals from earthquakes and volcanoes in future.

© Scoop Media

 
 
 
Business Headlines | Sci-Tech Headlines

 

Retail: Post-Lockdown Retail Card Spending Picks Up

The rise in retail card spending was boosted by sales of furniture, hardware, and appliances, Stats NZ said today. “For a third consecutive month, card spending on the long-lasting goods (durables) remained at higher levels than last year, after ... More>>


Contact: Business Drops, New Generation On Hold

New Zealand’s second-largest energy company Contact Energy (‘Contact’) released its full year financial results for the 12 months to 30 June 2020 (‘FY20’) this morning. More>>

Mining: OceanaGold Announces Receipt Of WKP Mining Permit

MELBOURNE, Australia, Aug. 6, 2020 /CNW/ - OceanaGold Corporation (TSX: OGC) (ASX: OGC) (the 'Company') is pleased to announce it has received the mining permit for Wharekirauponga ('WKP') on the North Island of New Zealand. ... More>>

ALSO:

Economy: COVID-19 Lockdown Has Widespread Effects On Labour Market

In the June 2020 quarter, the seasonally adjusted unemployment rate fell to 4.0 percent, down from 4.2 percent last quarter, while underutilisation rose, Stats NZ said today. More>>

ALSO:

NZ Post: New Research By NZ Post Shows Online Shopping Grew 105% In Alert Level 3

New research by NZ Post into how the COVID-19 response has impacted the way Kiwis shop online, shows online shopping increased 105%* when the country moved into Alert Level 3, and may have changed the way Kiwis shop permanently. Online spend peaked ... More>>

ALSO:

Banking: Westpac NZ Lowers Merchant Fees For Small Businesses

Westpac NZ is rolling out a new merchant fee pricing structure that will lead to cost savings for more than 10,000 small and medium Kiwi businesses, and could make contactless transactions more widely available for customers. On 1 September, most ... More>>

Antarctica NZ: Ice-Olation

Antarctica New Zealand is gearing up for a much reduced season on the ice this year and a very different deployment to normal! Before they head to one of the remotest places on the planet, all personnel flying south with the New Zealand programme will ... More>>

ALSO:

QV Valuations: July House Price Index Illustrates Market Resilience

According to the July 2020 QV House Price Index (HPI) results out today , property values recorded a marginal increase, up 0.2% over the month. This is somewhat of a turnaround from June, after the national index edged 0.2% lower. More>>

ALSO:

Property: Queenstown Rents Experience Biggest Drop In Seven Years

Rental prices in the Queenstown-Lakes district saw the biggest annual percentage drop in seven years after falling 28 per cent on June last year, according to the latest Trade Me Rental Price Index. Trade Me Property spokesperson Aaron Clancy said ... More>>

Seismology: The Quiet Earth

As many daily activities came to a halt during lockdown, the Earth itself became quiet, probably quieter than it has been since humans developed the technology to listen in. Seismologists have analysed datasets from more than 300 international ... More>>

RNZ: James Shaw Says Kiwibank, Not Ministers Should Decide On Investors

Climate Change Minister James Shaw says Kiwibank's decision to stop doing business with companies dealing in fossil fuels is the right one. More>>

ALSO:

FMA: Kiwis Confident Financial Markets Will Recover From COVID-19, Plan To Increase Investments

Despite the majority (60%) of investors experiencing losses as a result of COVID-19, the outlook on investing remains positive, according to a Financial Markets Authority (FMA) survey. Most Kiwis (71%) were optimistic that the pandemic will pass eventually ... More>>

FIRST Union: Warehouse Using Covid For Cover As Extensive Restructure Makes Everyone Worse Off

(FIRST Union comments on The Warehouse consultation and proposed restructure) 'Unfortunately the Warehouse have done the disappointing thing and used Covid-19 to justify a bunch of operational business decisions that will leave hundreds of workers without jobs ... More>>

ALSO: