Pre-, post-, and coeruptive datasets. (A and B) Marine gravity anomaly derived from satellite altimetry (V31.1 and V32.1, respectively). The subaerial island is outlined in gray. (C) Change in marine gravity anomaly between (A) and (B). (D and E) Vertical gravity gradient (VGG) data from satellite altimetry (V31.1 and V.32, respectively). (F) Change in VGG between (D) and (E). (G) Pre-eruption bathymetry, (H) Post-eruption bathymetry (see Materials and methods) and (I) change in bathymetry between (G) and (H) attributed to the Hunga eruption of January 2022. The outline of the caldera (dotted line green) and the Universal Transverse Mercator (UTM) coordinates (zone 1) are shown in red for reference. Credit: Scientists progress (2023). DOI: 10.1126/sciadv.adh3156
A small team of geologists, volcanologists and Earth scientists from the Carnegie Institution for Science, Earth and Planets Laboratory, USA, GNS Science, Wairakei Research Center, New Zealand, Auckland University of Technology, New Zealand, from the University of Auckland, New Zealand, and the Ministry of Land and Natural Resources, Tonga, have partially mapped the state of the magma system beneath the Hunga volcano before and after its eruption of 2022.
In their article published in the journal Scientists progress, The group describes how they used two types of technology to learn more about the magma reservoirs beneath the South Pacific volcano.
In January 2022, the Hunga volcano experienced a massive eruption, so strong that its caldera completely collapsed, its plume reached 58 kilometers into the mesosphere and the tsunami it generated reached the coasts of the United States and from Japan. However, the study of the volcano and its eruption has proven difficult due to its underwater location. In this new effort, the research team took a different approach to learning more about the magma chambers beneath the volcano.
Because it is difficult to deploy conventional sonar equipment in such an underwater environment, the research team instead used data from satellites so sensitive they can measure tiny differences in sea levels worldwide. Slight differences in sea level above a volcano, due to magma inside the chambers, the researchers noted, could be used to measure the amount of magma inside those chambers and also to map their size.
To this end, they analyzed satellite radar pulse data as well as multibeam bathymetry data for the region. Together, the two data sources allowed researchers to create partial maps of the magma chambers beneath the volcano, one dating from before the eruption, the other from after. – allowing a comparison.
By studying their maps, the research team discovered that there are three pockets of magma beneath the volcano, two that are liquid and a third that is mostly solidifying mush. They also found that the majority of the magma involved in the eruption came from a central chamber and that about 30% of its contents were expelled from the volcano during the eruption, leading to the collapse of the caldera.
The researchers also discovered the presence of a channel connecting the two liquid-filled chambers, which helped replenish much of the magma lost in the central chamber. They expect that further study of satellite data will reveal more details about the chambers beneath the volcano.
More information:
Hélène Le Mével et al, The magmatic system under the Hunga volcano before and after the eruption of January 15, 2022, Scientists progress (2023). DOI: 10.1126/sciadv.adh3156
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Quote: Mapping of the magma chambers under the Hunga volcano before and after the 2022 eruption (December 22, 2023) retrieved on December 23, 2023 from
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