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The Active Hunga Volcano

Tonga

Hunga Volcano's subaerial landscape during a smaller surtseyan eruption in the lead up to the January 2022 phreatoplinian event (Photo credit: Taaniela Kula).

Hunga Volcano’s subaerial landscape during a smaller surtseyan eruption in the lead up to the January 2022 phreatoplinian event (Photo credit: Taaniela Kula).

Geological Period

Pleistocene to Holocene

Main geological interest

Volcanology
Geomorphology and active geological processes

Location

Tofua Volcanic Arc, Tonga
20°32’50”S, 175°23’25”W

Hunga Volcano’s subaerial landscape during a smaller surtseyan eruption in the lead up to the January 2022 phreatoplinian event (Photo credit: Taaniela Kula).

This volcano shocked our world with one of the most extraordinary geological events ever observed.

We must conserve Hunga in the collective memory of humankind to ensure that its extraordinary geoheritage is not forgotten beneath the ocean. The record-breaking 15/01/2022 phreatoplinian eruption encompassed the deepest caldera collapse ever observed (~1kilometer-deep), ~9km3 of material ejected to the highest altitude ever recorded (~58kilometers), the first observation of an eruption reaching the mesosphere, deadly ~45meter-high megatsunami, sonic booms which traversed Earth four times, and destructive pyroclastic density currents. It caused devastating impacts and death in communities as distant as Peru.
Unprecedented observations before, during and after the eruption make Hunga an unparalleled reference for understanding volcanic hazards and promoting resilience.

As seen from space: a satellite image of the January 2022 eruption. The first eruption observed to reach beyond the stratosphere and into the mesosphere. (Imagery credit: CSU/CIRA & JMA/JAXA).

As seen from space: a satellite image of the January 2022 eruption. The first eruption observed to reach beyond the stratosphere and into the mesosphere. (Imagery credit: CSU/CIRA & JMA/JAXA).

  • Geological description

Hunga Volcano is a remarkable site located in the SW Pacific Ocean. This predominantly submarine volcano rises approximately 1,800 meters above the surrounding seafloor. At its summit, there is a central caldera 5 kilometers in diameter and ~1 kilometer deep. Two islands, Hunga-Tonga and Hunga-Ha’apai, emerge from the northern and western caldera rim.
Situated within the Tofua Volcanic Arc -Earth’s fastest-converging and most seismically active subduction boundary– the volcano formed during the Late-Pleistocene period (0.5 Ma) in response to subduction of the Pacific Plate beneath the Indo-Australian Plate. This geological setting is characterized by ongoing tectonic activity and active volcanic processes. The site has witnessed historical eruptions in 1912, 1988, 2009 (Bohnenstiehl, 2013) and 2014-15 (Cronin et al., 2017), with earlier eruptions dated at 210AD and 1125AD.
Hunga Volcano’s phreatoplinian eruption in January 2022 is one of the most extraordinary geological events ever observed with modern technology, making the site a global scientific reference.
Scientists closely study Hunga Volcano to gain insights into its formation, eruptive behavior, and hazards. By understanding the complex geological processes shaping this site, we can enhance our knowledge of similar volcanic systems on earth and other planets (Garvin et al., 2018), and improve mitigation strategies for volcanic hazards.

  • Scientific research and tradition

Distinguished researchers have investigated Hunga Volcano’s eruptive activity & hazards (Bohnenstiehl et al., 2013; Cronin et al., 2017), notably volcanic tsunami (Lane, 2022; Purkis et al., 2023). The site offers significant insights into volcanic systems, including the evolution of new volcanic islands (Garvin et al., 2018), contributing to science and geoheritage (Nemeth, 2022) traditions.

Comparative pre-eruption (2016) and post-eruption (2022) bathymetric-topographic models of Hunga Volcano, showing the dramatic caldera collapse of the 15/01/2022 eruption (Garvin and Slayback, 2023).

Comparative pre-eruption (2016) and post-eruption (2022) bathymetric-topographic models of Hunga Volcano, showing the dramatic caldera collapse of the 15/01/2022 eruption (Garvin and Slayback, 2023).

  • Reference

Bohnenstiehl, D.R. et al. (2013) ‘Underwater acoustic records from the March 2009 eruption of Hunga Ha’apai-Hunga Tonga volcano in the Kingdom of Tonga’, Journal of Volcanology and Geothermal Research, 249, pp. 12–24. Available at: https://doi.org/10.1016/j.jvolgeores.2012.08.014.

Cronin, S. et al. (2017) ‘New Volcanic Island Unveils Explosive Past’, Eos, 98. Available at: https://doi.org/10.1029/2017EO076589.

Garvin, J.B. et al. (2018) ‘Monitoring and Modeling the Rapid Evolution of Earth’s Newest Volcanic Island: Hunga Tonga Hunga Ha’apai (Tonga) Using High Spatial Resolution Satellite Observations’, Geophysical Research Letters, 45(8), pp. 3445–3452. Available at: https://doi.org/10.1002/2017GL076621.

Lane, E.M. (2022) ‘Atmospheric waves reinforced tsunami after Tongan eruption’, Nature, 609(7928), pp. 677–678. Available at: https://doi.org/10.1038/d41586-022-01855-0.

Németh, K. (2022) ‘Geoheritage and geodiversity aspects of catastrophic volcanic eruptions: Lessons from the 15th of January 2022 Hunga Tonga – Hunga Ha’apai eruption, SW Pacific’, International Journal of Geoheritage and Parks, 10(4), pp. 546–568. Available at: https://doi.org/10.1016/j.ijgeop.2022.08.003.

Purkis, S.J. et al. (2023) ‘The 2022 Hunga-Tonga megatsunami: Near-field simulation of a once-in-a-century event’, Science Advances, 9(15), p. eadf5493. Available at: https://doi.org/10.1126/sciadv.adf5493.

  • Author(s)

Taaniela Kula.
Ministry of Lands, Survey, Planning and Natural Resources, Kingdom of Tonga.

Shane Cronin.
University of Auckland, New Zealand.

Gary Lee.
The Pacific Community (SPC), Fiji.

James Garvin.
NASA (Goddard Space Flight Center), USA.

Paul Taylor.
Australian Volcanological Investigations, Australia.

Mike Williams.
National Institute of Water and Atmospheric Research (NIWA), New Zealand.

Károly Németh.
Saudi Geological Survey, Kingdom of Saudi Arabia.

Sung-Hyun Park.
Korea Polar Research Institute, Korea.

Isobel Yeo.
National Oceanography Centre Southampton, UK.

Mike Clare.
National Oceanography Centre Southampton, UK.

Emily Lane.
National Institute of Water and Atmospheric Research (NIWA), New Zealand.

Sarah Seabrook.
National Institute of Water and Atmospheric Research (NIWA), New Zealand.

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