2022-06-14 (IPMA)
Scientists explain the unusual tsunami that followed the Hunga Tonga-Hunga Ha‘apai volcano explosion on Jan. 15th 2022
The tsunami that followed the colossal explosion of the Hunga Tonga-Hunga Ha‘apai volcano on Jan. 15th 2022 was exceptional as it exhibited global reach, higher propagation speeds, unexpected wave heights in the far-field, and an unprecedented duration. An international team, led by a researcher from the Instituto Português do Mar e da Atmosfera (IPMA), Portugal, explained the mechanism behind the generation and propagation of this unusual tsunami in their recently published work in Nature magazine.
In this study, the team analyzed satellite, sea-level and atmospheric data worldwide and demonstrated through numerical and analytical models that the tsunami was driven by an acoustic-gravity wave caused by the volcano explosion and travelled several times across the globe. In their findings, the authors provide the exact explanation of the globally observed tsunami and suggest hazard implications for such events.
“The violent explosion of the Hunga Tonga-Hunga Ha'apai volcano in the South Pacific was a source of both noticeable atmospheric waves and an exceptionally fast-travelling global tsunami with minimal dissipation in the far-field. This was the first time that a volcano-triggered tsunami was globally recorded by modern, worldwide dense instrumentation, thus providing a unique opportunity to investigate the role of air-water coupling processes in tsunami generation and propagation.” Explains Rachid Omira from IPMA, the first author of the published article.
“The challenging part of studying the Tonga tsunami was to quantitatively explain all the observed tsunami features that were completely different from those of common tsunamis” says R. Omira.
“A fast-moving atmospheric wave able to excite the ocean surface and pump energy into it was our explanation for this tsunami that “jumped” from an ocean to another and reached the coast of Portugal 10 hours earlier than expected” adds Rachid Omira.
R. Omira acknowledged the collaboration of the co-authors from IPMA, Lisbon University, Cardiff University and IPNA-CSIC, Canary Islands, Spain and the support from FCT – Fundação para a Ciência e a Tecnologia I.P., Portugal through the project FAST- PTDC/CTA-MET/32004/2017.
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