Aaron Lojewski, who leads aura aura tours in Alaska, was lucky enough to photograph a bright pink “eruption”; of light in the night sky one February.
The same outrages at the Earth’s magnetic field that illuminated the sky behind Lojewski’s camera were also captured by seismometers on the ground, a team of researchers writes in the magazine. Seismological research letters.
Comparing data from all celestial cameras, magnetometers, and seismometers collected during three aura events in 2019, Carl Tape, a seismologist at the University of Alaska Fairbanks, and colleagues show that it is possible to combine a bright lantern display with seismic signals to observe the same phenomenon. in different ways.
Researchers have known for some time that seismometers are sensitive to magnetic fluctuations – and have worked hard to find ways to protect their devices from magnetic influences or remove these unwanted signals from seismic data. However, the aurora study provides an example of how seismometers could be paired with other instruments to investigate these fluctuations.
“It can be difficult to determine if these seismometer recordings have the same effect as what is happening in the 120-kilometer sky,” Tape said. “It helps to see the sky at the same time, to give more confidence in what you see from the signals at ground level.”
Aurora borealis, or northern lights, occur when the solar winds — plasma displaced from the surface of the Sun — correspond to a protective magnetic field around the Earth. The collision of particles creates colorful light in the sky and creates fluctuations in the magnetic field, sometimes called “storms” of the sun or space. Surface-mounted magnetometers are the main instrument used to detect these fluctuations, which can have a significant impact on electrical networks, GPS systems and other critical infrastructure. The aura is usually seen in winter at high latitudes such as Alaska.
The survey seismometers are part of the USArray Transportable Array, a network of temporary seismometers deployed throughout North America as part of the EarthScope project. The array in Alaska and western Canada was completed in 2017. In the fall. Aurora Paper is one of several included in the forthcoming SRL focus on EarthScope in Alaska and Canada.
These temporary seismic stations are not shielded from magnetic fields, unlike permanent stations, which are often surrounded by a metal, a nickel-iron alloy that directs magnetic fields around the instrument’s sensors. As a result, “I was blown away by how well you can capture magnetic storms across the array,” said Adam Ringler, a seismologist at the U.S. Geological Survey, in an SRL paper.
Last month, Ringler and colleagues published a paper showing how an array of 200-plus seismometers in Alaska can be used to capture weather in space, possibly augmenting 13 magnetometers operating in the state.
Together with full-sky camera data, seismic matrix data can help to understand the large changes in the magnetic field that occur in the east-west magnetic direction, adding a second dimension to typical studies of the aurora and north-south directions. magnetic storms, offers Tape and colleagues.
The researchers noted in their paper that a link between aurora boreal and magnetic resentment was first detected in Sweden in 1741, and a seismometer in Germany first detected an atmospheric magnetic event during a strong solar storm in 1994.
“People have been making these connections for 250 years,” Tape said. “It shows that we can still make discoveries, in this case with seismometers, to understand the aura.”
There may be northern lights in the sky next to you this week, also known as aurora borealis
Carl Tape and others, recording aura in seismometers throughout Alaska, Seismological research letters (2020). DOI: 10.1785 / 0220200161
Presented by the American Society of Seismologists
Citation: Alaska Seismometers Recorded Northern Lights (July 29, 2020), Retrieved from 2020 July 29, From https://phys.org/news/2020-07-alaskan-seismometers-northern.html
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