The Earth was beating every 4.5 minutes during the hours following the powerful Hunga-Tonga eruption in Oceania. A new study carried out by the Geosciences Barcelona researcher of the Spanish Research Council (GEO3BCN-CSIC), Jordi Díaz, analyzes the various types of seismic signals generated by the underwater volcanic explosion of the Hunga Tonga-Hunga Haʻapai and provides new details about the phenomena that occurred in this geological event.
On January 15, 2022, the Hunga-Tonga volcano, located in the Pacific Ocean, erupted causing one of the largest volcanic events in recent history. “The volcanic explosion caused the Earth to vibrate at very low frequencies, resonating for about eight hours,” Diaz explains. This record of low-frequency resonant signals, clarifies the researcher, had only been previously detected after the eruptions of Pinatubo (Philippines, 1991) and El Chichón (Mexico, 1982).
The 2022 Hunga-Tonga eruption stimulated low-frequency and long-lasting coupling between the atmosphere and the solid Earth which likely resulted from the excitation of Earth's normal modes.@JDiazCusi @GEO3BCN_CSIC https://t.co/XW7jDpCKBp pic.twitter.com/gt5XsMrJOD— Communications Earth & Environment (@CommsEarth) November 18, 2022
In this new article, published in the journal Communications Earth & Environment from the Nature group, Díaz focuses on the temporal evolution of the eruptive process, the propagation of atmospheric waves around the Earth, and long-duration, low-frequency seismic signals around the world after the main event.
The atmospheric waves circled the Earth twice
According to the GEO3BCN-CSIC scientist, it is the first time that the passage of atmospheric waves has been recorded with seismometers for such a long time. “The pressure wave was so powerful that, even after going around the Earth twice, it still manages to vibrate the ground and be detected by a seismometer,” he poits out. Seismic networks identified the passage of this wave up to five times over three and a half days.
“The work is further proof that seismometers not only allow for the detection of earthquakes, but that they can be useful for detecting other types of signals,” states the scientist from Geosciences Barcelona.
The variation in atmospheric pressure generated by this explosion spread throughout the planet, producing variations that were detected by various types of sensors. “To carry out the work, seismic data has been collected from the main networks worldwide, as well as stations of the networks of the Institut Cartogràfic i Geològic de Catalunya and the National Geographic Institute,” Diaz claims.
Diaz, J. Atmosphere-solid earth coupling signals generated by the 15 January 2022 Hunga-Tonga eruption. Commun Earth Environ 3, 281 (2022). https://doi.org/10.1038/s43247-022-00616-1