“Before the eruption, the caldera was about 120m (396ft) high. Now it’s a kilometer deep,” says Mackay. “Additionally, we found pyroclastic flows – turbulent, dense, violent rivulets that have flowed along the seafloor – at least 60km (37 miles) away, radiating from all angles.” an endeavour funded by the Nippon Foundation, a non-profit based in Japan which has helped underwater research since 1962. The programme is also supported by the General Bathymetric Chart of the Oceans (Gebco), an organisation aiming
