New trigger proposed for record-smashing 2022 Tonga eruption: previously unstudied data from a seismic wave, detected 750 kilometers from the seamount, may bolster tsunami early-warning systems.

Fifteen minutes before the massive January 2022 eruption of the Hunga Tonga-Hunga Ha’apai volcano, a seismic wave was recorded by two distant seismic stations. Now, researchers argue that similar early signals could be used to warn of other impending eruptions in remote oceanic volcanoes. The researchers propose that the seismic wave was caused by a fracture in a weak area of oceanic crust beneath the volcano’s caldera wall. That fracture allowed seawater and magma to pour into and mix together in the space above the volcano’s subsurface magma chamber, explosively kickstarting the eruption. The research was published in Geophysical Research Letters, an open-access AGU journal that publishes high-impact, short-format reports with immediate implications spanning all Earth and space sciences. The results build on the researchers’ previous work monitoring remote volcanoes. In this case, the Rayleigh wave, a type of seismic wave that moves through the Earth’s surface, was detected 750 kilometers (approximately 466 miles) from the volcano.

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New trigger proposed for record-smashing 2022 Tonga eruption