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Alaskan seismometers record aurora borealis



Alaskan seismometers record aurora borealis

Aurora near Poker Flats in Alaska. Credit: Aaron Lojewski, Fairbanks Aurora Tours

Aaron Lojewski, who leads Aurora sightseeing tours in Alaska, was fortunate to be able to photograph a “eruption”

; of a bright pink light in the night sky in a night sky in February evening.

Seismometers on Earth also captured the same disturbances in the Earth’s magnetic field, which illuminated the sky for the Lojewski camera. Seismological research papers.

By comparing data collected by all-sky cameras, magnetometers and seismometers during the three Aurora events in 2019, seismologist Carl Tape and colleagues at the University of Alaska Fairbanks show that it is possible to compare strong light images with seismic signals and observe the same phenomenon. in different ways.

Scientists have known for some time that seismometers are sensitive to magnetic fluctuations – and have worked hard to find ways to protect their instruments from magnetic influence or to remove these unwanted signals from their seismic data. However, the aurora study offers an example of how seismometers could be paired with other instruments to study these fluctuations.

“It can be difficult to conclude that these seismometers have their origins in the same influence as what is happening in the sky 120 kilometers up,” Tape said. “It helps to have a simultaneous view of the sky to gain more confidence in what you see from ground-level signals.”

Northern lights or aurora borealis occur when solar winds – plasma ejected from the Sun’s surface – meet a protective magnetic field that surrounds the Earth. The collision of particles creates colored light in the sky and causes the magnetic field, which is sometimes called solar or cosmic “storms”, to fluctuate. Magnetometers located on the earth’s surface are the primary tool used to detect these fluctuations, which can significantly affect electrical networks, GPS systems and other critical infrastructure. The aurora borealis is commonly seen in winter in high mountain areas such as Alaska.

The seismometers in this study are part of the USArray Transportable Array, a network of temporary seisometers located in North America as part of the EarthScope project. The file in Alaska and Western Canada was completed in the fall of 2017. Aurora Paper is one of several included in the forthcoming SRL section on EarthScope in Alaska and Canada.

These temporary seismic stations are not protected from the magnetic field, unlike permanent stations, which are often masked into a metal, nickel-iron alloy, which directs the magnetic fields around the sensors of the device. As a result, “I was blown away by how well you can detect magnetic storms across a range,” said seismologist Adam Ringler, an American geological survey co-author on SRL paper.

Last month, Ringler and colleagues published a paper demonstrating how Alaska’s 200-plus field seisometers can be used to record space weather, potentially expanding the 13 magnetometers in operation in the state.

Together with data on all types of sky, seismic field data can help understand the strong variations in the magnetic field that occur in the east-west magnetic direction and add a second dimension to typical north-south directional studies of aurora and other magnetic storms, Tape and colleagues suggest .

The researchers said that the link between the aurora borealis polar polars and magnetic disturbances was first discovered in Sweden in 1741, and that a seisometer in Germany detected a magnetic event generated by the atmosphere for the first time during a severe solar storm in 1994.

“People have been making these connections for 250 years,” Tape said. “It shows that we can still discover discoveries, in this case seismometers, to understand the aurora borealis.”


The northern lights, called “aurora borealis”, may have been approaching you near the sky this week


More information:
Carl Tape et al., Recording of Aurora on Seisometers in Alaska, Seismological research papers (2020). DOI: 10.1785 / 0220200161

Provided by the Seismological Society of America



Citations: Alaskan Seismometers Record Northern Lights (2020, July 29) Obtained on July 29, 2020 from https://phys.org/news/2020-07-alaskan-seismometers-northern.html

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