Underwater eruption Kavachi is one of the Pacific Ocean’s more active submarine volcanoes,
Underwater eruption Kavachi is one of the Pacific Ocean’s more active submarine volcanoes, and was caught erupting by a NASA satellite a couple of weeks ago. Named after a local sea god, it has appeared above the waves at least nine times only to be eroded away again by the sea since its first recorded eruption in 1939. Its typical activity is Surtseyan, named after an island that appeared off Iceland in 1969, in which magma-water explosions eject peacocks tail shaped jets of steam, ash and glowing bonbs. Its products are basaltic to andesitic. The volcano is in the Solomon Islands, only 30km north of the trench that marks the subduction of the Indo-Australian plate beneath the Pacific one, close to a regional spreading centre where new oceanic crust is being extruded. It rises 1,200 metres from the sea floor. The plume in the photo is made of small particles of fragmented lava called hyaloclastite, along with some gases. Such eruptions also produce rafts of floating pumice, frothy glassy gas rich lava that has such a low density it floats (even in the bathtub). They can moon around the ocean for ages before washing up with the currents on some faraway beach. This month in Australia I have been wondering about the source of a very light grey to white pumice with thin tiny needles of dark hornblende within that I have seen washed up all up the east coast beaches from Sydney to Byron Bay…there are many possible suspects out there in the ocean. Loz Image credit: NASAhttp://earthobservatory.nasa.gov/NaturalHazards/view.php?id=83025&src=fbhttp://www.volcanodiscovery.com/kavachi.html -- source link
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