Blast: A plume of sulphur and molten lava erupts from the West Mata Volcano
nearly 4,000 feet beneath the Pacific Ocean, south of Samoa

Researchers are calling it a major geological discovery after a submersible robot witnessed the eruption during an underwater expedition in May near Samoa.

The high-definition videos were revealed last week at a geophysics conference in San Francisco.

Mission: A robotic arm collects samples at the scene of the eruption

Scientists hope the images, data and samples obtained during the mission will shed new light on how the ocean’s crust was formed and how the earth behaves when tectonic plates ram into each other.

‘It was an underwater Fourth of July,’ said Bob Embley, a marine geologist for the National Oceanic and Atmospheric Administration.

‘Since the water pressure at that depth suppresses the violence of the volcano’s explosions, we could get the underwater robot within feet of the active eruption.’

The eruption was a spectacular sight: Bright-red magma bubbles shot up releasing a smoke-like cloud of sulphur, then froze almost instantly as they hit the cold sea water, causing black rock to sink to the sea floor. The submersible hovered near the blasts, it’s robotic arm reaching into the lava to collect samples.

Witnessing the deep-sea volcanic eruption was 25 years in the making.

Researchers from NOAA and the National Science Foundation had studied deep-sea volcanoes extensively but never witnessed an eruption. Eighty percent of the earth’s volcanic activity occurs in the sea, but their underwater locations have complicated scientific efforts to this point.

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