Earthquakes and tsunamis affect the ionosphere much more strongly than previously thought

Earthquakes and tsunamis affect the ionosphere much more strongly than previously thought
Earthquakes and tsunamis affect the ionosphere much more strongly than previously thought
Anonim

Disturbances in the ionosphere over Japan after the powerful 2011 earthquake were similar to a series of strong X-class solar flares.

Researchers have known for decades that earthquakes and tsunamis send atmospheric pressure waves into the uppermost part of the Earth's atmosphere. There, in the ionosphere, the waves are jamming GPS signals and interfering with radio communications, just as solar flares do. Earthquakes, it turns out, can mimic space weather.

A new article, published in the research journal Space Weather, shows that earthquakes and tsunamis can, in fact, affect the ionosphere much more strongly than previously thought.

"On March 11, 2011, a magnitude 9.0 earthquake struck off the east coast of Honshu Island, Japan, causing a ferocious tsunami as well as unprecedented ripples in the interaction between space and the atmosphere," said the authors of the report, led by Min-Yang Chou of the University's Atmospheric Corporation Research (UCAR) in Boulder, CO.

Using satellites and ground-based GPS receivers, Zhou and his colleagues took a close look at what happened to the ionosphere over Japan after the earthquake. As expected, she was disturbed. Surprisingly, however, the ionospheric disturbances did not stop after the initial earthquake and tsunami; they continued for many more hours. Reason: reflected tsunami.

"The tsunami was reflected by several sources such as seamounts, islands and ridges," Chow says. “These reflections created several concentric tsunami waves in the ocean.

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“Bouncing back and forth across the Pacific Ocean, the reflected tsunamis kept the ionosphere over Japan disturbed for a full 46 hours.

Researchers once thought that only the sun could disrupt the ionosphere so much. Solar flares wash over the upper part of our atmosphere with ultraviolet and X-rays, sending ionization waves pulsing through the ionosphere.

Sounds familiar? Earthquakes and tsunamis have the same effect. In fact, Chou says, the disturbances over Japan were akin to a series of powerful X-class solar flares.

In a sense, the tsunami is even worse. The disturbances they generate last for several days and can be very complex due to reflections. Reflected waves near Japan in 2011 caused a chaotic night flicker of GPS satellite signals - enough to make some GPS devices completely disorientated.

As events unfold in 2020, the Sun is experiencing one of the deepest solar minimums of the last century. There are no solar flares. At times like this, earthquakes and tsunamis rule space weather, simulating stormy space weather in the absence of actual solar activity.

Now more than ever, "understanding how natural hazards such as tsunamis and earthquakes affect our upper atmosphere and cause changes in the space environment around Earth is critical," Zhou says.

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