Undersea Volcano Erupting Near Samoa

An undersea volcano off the coast of Samoa recently started erupting and is billowing “smoggy” water for several miles, scientists reported Tuesday.

The volcano, Vailuluiu, is 28 miles east of Taiu Island, on the eastern side of Samoa. It rises 16,400 feet from the ocean bottom and reaches to within 2,000 feet of the surface.

Scientists at the Scripps and Woods Hole institutes of oceanography suspected the volcano might be active after a swarm of earthquakes was reported at the volcano in 1995. They mapped the volcano during a research cruise in 1999.

This spring, they returned and for the first time found evidence the volcano was erupting. Instruments showed that “smoggy” water filled the volcano’s crater and extended five miles from the summit.

The team left underwater microphones near the volcano and on the crater floor to record the low rumblings that indicate if magma is stirring within Vailuluiu.

Scientists are excited about the finding because few undersea volcanoes in the world are accessible to study. “We have access to the buildup of a volcano that will eventually become an island,” said Anthony Koppers, a scientist at Scripps who studies undersea volcanoes.

Studying Vailuluiu could answer a long-standing question about the origin of the Samoan island chain and whether it is related to activity of crustal plates.

An alternative is that, like Hawaii, the Samoan islands are the result of “hot spots” that spew out magma. The volcanoes over hot spots eventually cool and become chains of islands as the earth’s crustal plates move past. Since the mid-1990s, other research teams have been studying Loihi, an undersea volcano 3,000 feet below the surface south of Hawaii. “Comparing the two is very interesting,” said Koppers.

Since the Vailuluiu’s summit is so far beneath the surface, it could not be seen from the research vessel, but was detected with sonar and instruments that can measure the amount of particulates clouding the water.