Tsunamis are one of the most destructive natural disasters. Anticipating this deadly and destructive event, which can be triggered by an earthquake, underwater volcanic eruption or landslide, is a major challenge.
To complement existing land and marine tsunami detection systems and save valuable time in alerting people at risk, Jet Propulsion Laboratory Working on the Atmospheric Observatory (JPL) of NASA. The U.S. space agency claims that depending on the distance between the source and the shore, it can warn about a tsunami up to an hour in advance.
Guardian (GNSS Upper Atmosphere Real-time Disaster Information and Warning Network), using data from satellite positioning systems by analyzing signal disturbances in the ionosphere.
“Rumble” detection of tsunamis in the ionosphere
When a tsunami occurs, it creates a large movement on the surface of the water that moves the wind. The latter produces low-frequency sound waves and gravitational waves. When they interact with the electrically charged layers of the ionosphere, they can interfere with the signals of navigation satellites. It is precisely these disturbances that the Guardian can detect. ” It is already one of the fastest monitoring instruments of its kind: in 10 minutes, it can produce a kind of snapshot of the roar of a tsunami hitting the ionosphere. “, NASA explains in its press release.
Currently, the system is being tested in the Pacific Ring of Fire. It borders the entire circumference of this sea where 452 volcanoes are distributed. According to the National Oceanic and Atmospheric Administration (NOAA), 78% of the more than 750 confirmed tsunamis between 1900 and 2015 occurred in this region.
This animation shows how the energy waves from the Tohoku-oki earthquake and tsunami. On March 11, 2011, they pierced the Earth’s ionosphere near Japan, disrupting the electron density. These disturbances are tracked by tracking GPS signals between satellites and ground receivers. © NASA/JPL-Caltech
The next step: coverage expansion
The project team has developed a website for professionals only. They can study the state of the ionosphere in real-time to study the links of individual satellite stations in the GNSS network. They can detect warning signs of a tsunami within minutes of an event.
” We view Guardian as a complement to land and marine instruments such as seismometers, buoys and tide gauges. They are very effective, but lack proper open sea protection,” says Siddharth Krishnamurthy. He is a member of the Computer Development Group at the Jet Propulsion Laboratory. The group will continue to build the Guardian to expand its coverage. Its purpose: Capable of automatically generating alerts in case of danger.
