A rising volcanic plume from an unknown source was observed on 9–11 August 2006 in the Vava'u Island group in the northernmost islands of Tonga [Matangi News Online, 2006]. On 12 August, the crew on board the yacht Maiken, sailing west from Vava'u to Fiji, encountered “a vast, many miles wide, belt of densely packed pumice” floating on the water (F. Fransson personal communication, 2006). Later, the crew sailed south and discovered that the source of the pumice was a newly erupting submarine volcano near Home Reef (18.991°S, 174.767°W) (Figure la).
The submarine Home Reef volcano last erupted in 1984, creating a small, temporary island, 1500 meters long×500 meters wide [Smithsonian Institution, 1984]. The 1984 eruption also produced large amounts of pumice that rafted away with the currents, and over the following year the floating pumice traveled to beaches as far away as Fiji and Australia [Smithsonian Institution, 1985; Bryan et al., 2004]. With time, these ocean-voyaging pumice fragments can have far-reaching ecological effects as a transportation mechanism for some marine organisms [Bryan et al., 2004].