Ash Plume From Hunga Tonga-Hunga Ha'apai Strands Tourists

The steam-and-ash plume from Hunga Tonga-Hunga Ha'apai, seen on January 7, 2015 via Terra/MODIS. Image: NASALast month I noted that a new submarine eruption had started at Hunga Tonga-Hunga Ha'apai in the Pacific Ocean. At the time, the eruption appeared to be fairly minor, with some discoloration of the sea and a steam plume. However, since early January, the activity has intensified to the point where air traffic in and out of Tonga has been disrupted, leaving hundreds of people stranded. The volcano produced a ~9 km (30,000 foot) ash plume (based on reports from pilots) and this might suggest that the eruption has either become stronger or that it is closer to the surface, where intense mixing of seawater and erupting lava cause phreatomagmatic explosions. Reports from people living on Tongatapu, only ~80 km from the eruption, say the plume has changes from more ash-rich to more steam-rich (and ...