RADARINDONESIANEWS. COM, JAKARTA — Tsunami waves are notoriously difficult to detect when they move quickly in the open ocean towards the coast. However, in the summer of 2025, scientists witnessed one of the tsunamis when the giant waves were rolling.
The earthquake on the Kamchatka Peninsula, Russia, in July 2025 was the strongest earthquake in the world for almost 15 years.
The earthquake measuring 8.8 on the Richter scale triggered a tsunami with a wave speed of more than 644km/hour. Within minutes, alarms sounded in various countries in the Pacific Ocean region, including Indonesia.
Millions of people were ordered to evacuate, including at least two million in Japan. However, when the wave rolls across the ocean, it creates ripples in the Earth’s atmosphere.
The ocean, which moves up and down across such a vast area, disrupts the atmosphere above, disrupting global satellite navigation signals. However, this disturbance also allows scientists to detect tsunamis almost directly (real-time).
Coincidentally, the previous day, the US space agency, NASA, had added an artificial intelligence (AI) component to its disaster warning system called Guardian. Thanks to this component, Guardian can report major events to scientists automatically.
About 20 minutes after the Kamchatka earthquake occurred, tsunami observers could tell that the tsunami was heading towards Hawaii, 30 to 40 minutes before the wave arrived.
Millions of people around the world can breathe a sigh of relief because the tsunami did not cause devastating damage. The waves that hit Hawaii reached a height of 1.7 meters, but only caused minor flooding and no serious damage.
The majority of a tsunami’s energy is dissipated in the open ocean, while the largest waves hit uninhabited areas. However, even if the impact of the tsunami was worse at that time, the extra minutes of early warning could be crucial.
This incident proves that NASA has a system that, under the right conditions, can detect tsunamis long before they arrive at the coastline.
How to?
The system listens for radio signals used by global navigation satellites when communicating with ground stations on Earth. Similar methods can detect volcanic eruptions, rocket launches and underground nuclear weapons tests.
“They can tell almost instantly, ‘there’s a tsunami,’” said Jeffrey Anderson, a data scientist at the US National Center for Atmospheric Research who helped develop the Guardian system.
Anderson admits that years ago, when he first heard about the development of the technology, he thought it sounded “a bit crazy”.
The idea of using radio signals between satellites in orbit and stations on the ground to detect tsunamis as they occur has been around for decades.
A number of academic papers in the 1970s discussed the principles of the system, but it was only in the 2020s that the system became a reality with the arrival of the Guardian.
In 2022, Anderson and scientists from NASA’s Jet Propulsion Laboratory in California, USA, published a study that introduced important details of the system.
The reason why navigation satellite signals can record tsunamis is because of the rising and falling movements of the sea.
When a tsunami begins to form in the open ocean, the waves may not be very high—perhaps between 10cm – 50cm.
“It’s almost invisible as it moves in the open ocean,” said Yue Cynthia Wu, an ocean engineering researcher at the University of Michigan who focuses on ocean wave dynamics.
Although tsunami forecasts are produced using the National Oceanic and Atmospheric Administration’s (NOAA) DART tsunami detection system which uses buoys anchored to the seabed, the Guardian system allows waves to be tracked as they occur.
This atmospheric tracking raises hopes that systems like Guardian could detect tsunamis as they emerge in the open ocean, before they reach incredible heights and hit shore.
This can provide the public with better early warning of what is to come, while also helping to avoid false alarms.
This technology can be applied to other phenomena besides earthquakes and volcanoes. This technology can even help detect nuclear explosions.
Ripples in the ionosphere, for example, have helped confirm that underground nuclear weapons tests had been carried out by North Korea in 2009.
Until now, tsunami monitoring networks have relied on seismometers, which analyze earthquakes around the world, as well as marine buoys that detect sudden changes in wave height.
However, these instruments do not provide a picture as comprehensive, or as fast as data from the ionosphere.
“Minutes are critical to tsunami evacuation, so Guardian’s early detection to me is a very important advance for tsunami safety,” said Harold Tobin, a seismologist at the University of Washington.
Anderson added that monitoring the ionosphere, instead of just seismometers, for example, means it will be easier to detect tsunamis triggered by events such as landslides.
Going forward, Guardian may not be the only such tool.
“In Europe, we are developing our own system,” said Elvira Astafyeva, senior researcher in geophysics and space sciences at the Paris Institute of Planetary Physics.
He and his colleagues hope to test their European system in the next few years and eventually help monitor large areas—including French territories in the Indian Ocean.
Hickey said tsunamis can also be detected through airglow, faint light emissions in the atmosphere that are also influenced by disturbances in the air.
Some limitations
The Guardian system itself is far from complete. Anderson said further improvements will allow the system to predict the behavior of waves moving across the ocean.
“This system allows not only automatic detection—but also automatic forecasting of what a tsunami will do next,” Anderson said.
Every 10 minutes or so, as the tsunami grows, such systems can automatically issue predictions about the final size of the wave, where it will hit land, and when.
There are still some limitations.
Diego Melgar, an expert on earthquakes, tsunamis and early warning systems at the University of Oregon, said the ionosphere “takes minutes to tens of minutes to respond” to a tsunami.
For people close to the tsunami epicenter, this period was still too late. “So for local warnings, that delay makes ionospheric signals too late to help.”
However, large tsunami waves can traverse entire ocean basins.
After the 2004 tsunami devastated coastlines around the Indian Ocean and killed an estimated 228,000 people, the waves took up to two hours to reach Sri Lanka from the earthquake’s epicenter off the coast of Indonesia.
The wave took seven hours before hitting the east coast.
Systems like Guardian could provide crucial early warning to these more distant communities should a similar wave occur.
“If something would travel a reasonable distance, then, yes, it would save lives,” Hickey said.[]
Post Views: 14
