Pacific scientist explores Tonga's underwater legacy

When the Hunga Tonga-Hunga Ha’apai volcano erupted on January 15, 2022, it produced the most powerful explosion in over 110 years, blasting a 58 kilometre high plume into the atmosphere.

It triggered a shockwave that circled the earth repeatedly, and sending tsunamis as far as the coast of South America.

Scientists estimate the force of the eruption to be equivalent to more than ten megatons of trinitrotoluene, hundreds of times stronger than the Hiroshima bomb.

Three years later, Fijian young scientist Tomasi Mara, a native in his early twenties, sailed into the footprint of this global event aboard Australia’s RV Investigator.

The expedition was coordinated by University of Tasmania, CSIRO (Marine National Faculty).

Mr Mara was selected as part of a major international expedition formally titled “Eruption, destruction and seafloor ecosystem recovery, 'Tonga’s 2022 eruption of the century' a multidisciplinary voyage focused on understanding how the eruption reshaped the seafloor, disrupted marine life and altered ocean systems.

Mission

Mr Mara said the mission brought together earth scientists, oceanographers and marine biologists to study geological change and ecosystem recovery in one of the world’s most dramatically transformed underwater environments.

“To stand above a volcano that shook the whole world and to contribute as a Pacific islander was incredibly meaningful. This eruption affected Pacific communities first,” Mr Mara said.

“Being part of understanding it is part of our responsibility as people of the ocean.”

He assisted in collecting and analysing deep sea rocks, ash and sediment samples from the seafloor, including material linked to the 850 metre deep crater formed during the eruption.

The team also surveyed benthic ecosystems – deep-sea habitats which initial studies showed were almost completely devastated in the months following the blast.

Growth

Mr Mara holds a Bachelor of Science in Environmental Science from the University of the South Pacific and a Postgraduate Diploma in Islands and Ocean Stewardship.

He currently works as a frontline monitor young scientist at the Social Empowerment and Education Programme (SEEP), where he focuses on environmental risk assessment, and community-based resilience.

His work involves conducting field research, analysing environmental data and engaging with rural communities to design locally driven adaptation strategies that strengthen their resilience against development, disasters and ecosystem degradation.

He said the voyage reinforced the importance of Pacific participation in global scientific research.

“Research about the Pacific should include Pacific voices,” he said.

“Our communities live closest to these events, so our perspectives matter in understanding risk, recovery and resilience.”

Mr Mara continues to contribute to post-voyage discussions on data interpretation and ecosystem recovery trends.

He hopes the findings will support better disaster preparedness for Pacific nations, inform future tsunami and volcanic hazard modelling and strengthen marine conservation work in the region.

“The Pacific is not just where we live, it is who we are. This experience showed me how powerful our ocean is and how important it is for our people to be part of the science that explains it,” Mr Mara said.

As discoveries from the expedition are released in the coming months.

Mr Mara’s journey stands as a powerful example of young Pacific scientists stepping into global research spaces and shaping knowledge that will help protect their communities for generations to come.