Tonga's volcano eruption a year ago was the most powerful ever, and had a profound impact on the surrounding sea floor.
Marine Geologist Dr Marta Ribó has been studying it and spoke to Charlotte Cook.
Tonga's volcano eruption a year ago was the most powerful ever, and had a profound impact on the surrounding sea floor.
Marine Geologist Dr Marta Ribó has been studying it and spoke to Charlotte Cook.