Images: Voyage to Vailulu'u
At hot spots, magma from the mantle bursts through the crust, creating seafloor volcanoes that often rise above the ocean surface to form islands. Island chains like Samoa form as overlying crustal plates move over the stationary injection point of the hot spot. (Jayne Doucette, WHOI)
A helicopter from the US Coast Guard1s Polar Star deploys one of five ocean-bottom hydrophones to record sound waves generated by any earthquakes or eruptions near Vailulu?u. After a year on the job, the hydrophones were retrieved in March 2001. (Stan Hart, WHOI)
The discovery of the active volcano Vailulu'u, just east of the Samoan Island of Ta?u, was "smoking gun" evidence that the Samoan Islands chain was created by a hot spot--not by other geological forces related to the nearby Tonga Trench.
The active undersea volcano, Loihi, is really one of a trio of active volcanoes, including Mauna Loa and Kilauea, which together comprise the island of Hawaii. (Jayne Doucette, WHOI)
Unlike Loihi, Vailulu'u is separated from the neighboring island of Ta?u and will eventually create a distinct island. That characteristic makes Vailulu'u much more scientifically valuable as a potential natural laboratory, says WHOI Senior Scientist Stan Hart. (Jayne Doucette, WHOI)
Over millions of years, the Pacific Plate moved northward and later westward over the top of the Hawaiian hot spot, carrying away islands formed at the hot spot. The result is a trail of progressively older islands and re-submerged, now-extinct seamounts, extending from the young Hawaiian islands to the older Emperor Seamount Chain.