Tonga Meteorological Services
New research has found that seismometers detected a Rayleigh wave 15 minutes before the massive eruption. Scientists now hope to be able to create warning systems based on this revelation.
In January 2022, the Hunga Tonga-Hunga Ha’apai volcano erupted with unprecedented force, destroying the island and sending a huge ash cloud over the Pacific.
This catastrophic event highlighted the challenge of predicting this type of eruption, which occurs frequently no apparent warning signs. However, recent research suggests that certain volcanic events may emit a subtle precursor signal before an eruption.
A study led by researchers at the University of Tokyo examined seismic data recorded by distant stations, including those in Fiji and Futuna, located in more than 750 kilometers from the eruption.
They found that about 15 minutes before the explosion volcanic, a specific type of seismic wave, called a Rayleigh wave, was detected by these seismometers. Although imperceptible to humans, the Rayleigh wave signaled activity below the volcano’s surface.
The team’s findings, in Geophysical Research Letters, suggest that this seismic wave could help develop early warning systems for similar future events. The Rayleigh wave can be used for these warnings, although current infrastructures do not have the capacity to interpret these volcanic eruption signals in real time, explains .
According to researchers, the Rayleigh wave likely resulted from a fracture under the volcano calderawhich allowed magma to enter the volcano’s chamber, causing a structural collapse that led to the eruption. This was the largest volcanic plume ever recorded, reaching 58 kilometers into the mesosphere in just 30 minutes – a record previously held by the 1991 eruption of Mount Pinatubo.
Integration of seismic data from remote stations can improve early warning systems by providing crucial minutes of notice before major eruptions. Although these methods would not be available in 2022, future underwater observatories may in the future apply this type of analysis to detect potential volcanic activity earlier.
If the Rayleigh wave signal proves effective in early warning systems, it could potentially reduce the impact of future eruptions – especially if they occur near densely populated regions.
