Wonderful and amazing things happen in nature all the time - auroras (dancing northern lights) are probably the most spectacular of them all. Earthquakes, volcanoes, tsunamis, hurricanes, lightning are some of the manifestations of nature's gigantic energy. Luckily, we now understand the reasons behind such amazing spectacles but they happen often enough to lose their wow factor.
A rare event, even though well-understood, still has the power to excite. Remember the first picture of the blue earth taken by astronauts from space and the excitement that it had caused.
Live observation of new land being formed in the South Pacific Ocean by the eruption of an underwater volcano (a seamount) was accidentally made in 2006. We all know that there are underwater volcanoes and they are as active as the run-of-the-mill volcanoes we see on land. These extinct volcanoes, seamounts and guyots, are part of the structure of the oceanic crust. In fact, the highest mountain in the world is a seamount - Hawaii's Mauna Kea, a dormant volcano that is more than 30,000 feet tall measured from its base - that is taller than Mount Everest!
As two continental plates move apart from each other (generally about 2 cm per year amounting to 2000 km in 100 million years), it opens up a crack in the earth's crust. Molten magma extrudes out from the crack, cools to form ocean ridge on either side of the crack (rift valley). Lot of the loosely deposited ridge is weathered by ocean currents and in time, the continental plates move further apart and also the ridge loses its height.
Seamount and guyots which are raised oceanic crust due to extinct volcanoes move with the plates. If originally the top of the seamount had risen above ocean water level then the wave action would have eroded the top and the flat top seamount becomes a guyot. As they move away from the plates, their distance below the ocean water level increases - they sink.
If the volcanic eruption deposits enough magma, the lava (solidified magma) can stick out of the ocean surface and forms a temporary island. Such islands do not always last for ever and most disappear after a period of days to moths or a few years.
How an island is formed is depicted by the following figure
1: Water vapour cloud 2: Cupressoid ash
3: Crater 4: Water 5: Layers of lava and ash
6: Stratum 7: Magma conduit
8: Magma chamber 9: Dike
The wow factor comes from the uniqueness of an observation when such an island is being formed in real time.
This is exactly what had happened in 2006 in the South Pacific near the Vava'u Islands in Tonga. I describe the amazing experience of the crew of the yacht Maiken in their own words:
The crew of the Yacht Maiken were sailing through the South Pacific near the Vava'u Islands in Tonga when they noticed that the water in the distance has gone a strange colour.
The crew documented the phenomenon in a series of remarkable pictures as they sailed into the formation to investigate, not realizing that a volcano was erupting just a few miles away
As the crew approached, the sea mysteriously turned to stone as the volcano pushed up new land