How Japan’s 2024 Earthquake Disrupted Satellite Signals

Earthquakes don’t just shake the ground. They also send waves rippling into the sky. These ripples, invisible to the eye, can interfere with the satellites we depend on for navigation, communication, and disaster response.

Now, researchers from Nagoya University in Japan have used satellite signals and over 4,500 ground sensors to map those sky ripples in 3D. This is the first time scientists have visualised how the 2024 Noto Peninsula Earthquake disrupted the upper atmosphere in such detail.

What scientists found after the quake

After a major earthquake, sound waves travel upward through the atmosphere. About 10 minutes after the Noto Peninsula quake hit on January 1, 2024, these waves reached a layer of the atmosphere called the ionosphere—60 to 1,000 kilometers above Earth.

The ionosphere contains charged particles that affect radio waves. When earthquake-generated sound waves hit this region, they disturb the electrons, creating a ripple effect like a stone in water. These disturbances can disrupt satellite signals.

Using data from Japan’s dense network of GNSS (Global Navigation Satellite System) receivers, the research team measured changes in electron density. These sensors track how much satellite signals slow down as they pass through the ionosphere. The slowdown reveals how many electrons are present.

By combining data from thousands of sensors, the team built 3D models showing how electron levels changed over time after the earthquake. They used a technique similar to a CT scan, called ionospheric tomography.

How sound waves ripple into space

What they found challenges older models. Earlier studies assumed sound waves come from a single point: the epicenter. But the 3D maps showed more complex patterns, especially south of the epicenter.

Waves didn’t just rise vertically. They started out tilted and straightened over time. To explain this, researchers modeled wave sources all along the fault line. Some waves were delayed by as much as 30 seconds.

This new approach fit the data much better.

“By including multiple distributed sources and time delays, our improved modeling provides a more accurate representation of how these waves propagate through the upper atmosphere,” said Professor Yuichi Otsuka, a lead researcher.

Why satellite disruptions matter

Dr. Weizheng Fu, the lead author, said these findings have real-world use. “Disturbances in the ionosphere can interfere with satellite communications and location accuracy,” he said. “If we understand these patterns better, we can protect sensitive technologies during and after earthquakes.”

The research, published in the journal Earth, Planets and Space, opens the door to using atmospheric data for better early warning systems—not just for earthquakes, but also for volcanoes and tsunamis.

Japan’s earthquake research doesn’t stop in the sky. The Japan Aerospace Exploration Agency (JAXA) is also working on a system to map earthquake damage on the ground using satellites and machine learning.

JAXA is training its system using detailed building damage records from the 2016 Kumamoto earthquakes. Over 200,000 buildings were damaged in that disaster. Local officials collected detailed on-site data, creating a rare dataset focused purely on quake damage, with no tsunami involvement.

By matching this data with radar images from its Daichi-2 and Daichi-4 satellites, JAXA hopes to assess damage within hours of future quakes.

Traditional aerial surveys can take hours or more. During the 2024 Noto quake, it took the government over half a day to estimate damage. Satellite radar can speed that up, working even at night or through clouds and rain.

“If we can assess the damage quickly, it will lead to faster rescue operations,” said Shiro Kawakita from JAXA.

There are still limits. Overhead satellite views may miss partial damage to lower floors of buildings. JAXA plans to improve accuracy by adding oblique-angle images.

Kumamoto Governor Takashi Kimura said he hopes the system can help across Japan. “I hope the lessons learned from the earthquakes can improve disaster response efforts nationwide,” he said.

These two fronts—sky and ground—show how Japan is combining science and technology to better understand and respond to earthquakes. And they hint at what the future of disaster readiness could look like.

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