Hunga Tonga-Hunga Ha’apai eruption images

A Japanese reader of The Volcanism Blog has sent in the following images of the Hunga Tonga-Hunga Ha’apai eruption, captured from a video taken on 18 March 2009.

These images clearly show that there are two active vents. The white plume consists mainly of steam, the dark masses are dark pyroclastic material projected violently upwards as water enters the magmatic vents, creating powerful phreatic explosions. The ragged-edged effect visible on the dark clouds is caused by larger fragments of ejected material following parabolic curves as they are hurled upwards and outwards, trailing smaller fragments behind them.

UPDATE: The video from which these images are clearly taken has turned up on the BBC News website: Underwater volcano erupts off Tonga. At the end of the video, around the point from which the final image reproduced above comes, voices can be heard off-camera saying ‘I think we should run away’, and ‘turn the boat around’.

For all our coverage of the Tonga eruption: Tonga « The Volcanism Blog.

Information
Global Volcanism Program: Hunga Tonga-Hunga Ha’apai – summary information about Hunga Tonga-Hunga Ha’apai (0403-04=)
Tonga volcanoes and volcanics – overview from the USGS