Tag Archives: volcano

A Rare Opportunity: Observing the life cycle of a young volcano

Cover image: Scientists aboard the Okeanos Explorer plan the remote operated vehicle (ROV)’s course to explore the emerging lava core inside Vailulu’u Seamount. This image shows a topographic map of the summit of Vailulu’u created using multibeam sonar imaging, with the ROV’s path charted along the red line. Image courtesy of NOAA Office of Exploration and Research.

The NOAA Ship Okeanos Explorer has kicked off its 2017 field season so far with amazing dives in the waters off American Samoa, a US territory in the southern Pacific Ocean. In February 2017, the expedition team explored the Vailulu’u Seamount, an underwater volcano located east of the  Samoan Island of Ta’u. This offered scientists a rare and exciting opportunity to observe the geological and ecological characteristics of an active underwater volcano.

This map shows a magnified view of the purple box in the inset map of the American Samoa. Vailulu’u Seamount is located 20 miles east of Ta’u Island in the American Samoa in the Pacific Ocean. Image courtesy of Woods Hole Oceanographic Institution.

Seamounts, like Vailulu’u, are undersea mountains formed by volcanic activity. As lava from the Earth’s interior erupts through the seafloor, it meets cold ocean water and hardens. As more lava erupts, hardens, and piles up, a seamount is formed.  If the eruptions continue for long enough, a seamount can actually rise tall enough to break the water surface, which is how islands are formed. Once seen as little more than hazards to undersea navigation, oceanographers have discovered that seamounts are hotspots of biological diversity. Underwater exploration has shown many seamounts to support a vast array of marine species and emphasized their importance as vital marine habitats.

An opportunity to explore Vailulu’u Seamount is particularly intriguing because of its status as the most active submarine volcano in the waters of American Samoa. Vailulu’u is thought to have erupted sometime between 2001 and 2005. This eruption formed a new 239 meter (nearly 1000 feet) tall lava cone inside the volcano’s crater. The lava cone, dubbed Nafanua after the fierce Samoan goddess of war, was discovered during an expedition in 2005 by scientists aboard a University of Hawaii research vessel using NOAA’s Pisces V manned submersible vehicle.

Multibeam bathymetric maps showing the emergence of the Nafanua volcanic core since 1999. Continued growth could bring the summit close to the surface of the ocean within the next few decades. Image courtesy of NOAA Office of Exploration and Research.

The discovery of the lava core was an important finding, as the chance to study an actively-forming underwater lava core is uncommon. Woods Hole Oceanographic Institution’s (WHOI) Senior Scientist, Stan Hart, said, “To actually have a documented case of an underwater volcano that has been constructed within a known period of time is very rare—this is one of those cases.” The area of Vailulu’u Seamount had originally been mapped using multibeam sonar imaging in 1991. From this baseline data, scientists estimated that the growth rate of the new lava core could have reached an average rate of 8 inches per day.

One particularly striking discovery of the 2005 University of Hawaii expedition occurred as the team explored the volcano’s hydrothermal vent system. Hydrothermal vents form at tectonically active areas under the ocean, where the seafloor is spreading or where tectonic plates are coming together. The seawater escaping from  hydrothermal vents can reach temperatures of over 700° F.  This superheated water is saturated in chemicals that fuel unique biological communities, many of which are found only in these very specific ecosystems. As the expedition team exploring Nafanua approached the lava cone’s hydrothermal vent area, they began to see large numbers of eels lurking among the surrounding rock pillars. When the submersible landed, scientists were surprised to see huge numbers of foot-long eels emerging from the rock caves and crevices surrounding the area – a dramatic illustration of the sort of unique communities that can found around vent systems. The memorable experience led scientists to dub this area “Eel City.”

Eels swarming on the summit of Nafanua in 2005. Image courtesy of NOAA Office of Exploration and Research.

During the February 2017 dive on Vailulu’u Seamount, the Okeanos Explorer collected further data on this active volcano in the Samoan region. The information collected during this dive will provide scientists with a critical view of the geochemistry of the early stages of a young volcano. In addition, comparing this dive to the ones in previous years will allow scientists to study the changes in biological communities that occur as an active volcano alters its environment.

Investigating the Vailulu’u Seamount has been just one highlight of the 2017 Okeanos Explorer field season thus  far. With many more ROV dives planned, there are doubtless many more intriguing discoveries to be made. Stay tuned to see what else the Okeanos Explorer finds as it continues to explore the unknown waters of the Pacific Ocean.

Discoveries from Leg 3 of the Okeanos Explorer’s EX1605 Expedition

Completed on July 10th, leg three of the NOAA Ship Okeanos Explorer‘s EX1605 expedition was chock-full of discoveries. The Okeanos‘s remotely operated vehicles (ROVs) conducted 22 dives, exploring many recently-mapped sites in the Mariana Trench Marine National Monument (MTMNM). They ventured where no ROVs have dove before.

Ship-based sonar mapping, along with ROV imaging and rock sampling, revealed new hydrothermal vent sites, deep-water coral reefs, the first petit-spot volcano found in US waters, and a new mud volcano in the MTMNM.

ROV Deep Discoverer images a newly discovered hydrothermal vent field at Chammoro Seamount.

Amid the geological findings, biologists cataloged many new species. The pictures and videos below highlight some of the newly-discovered inner-space aliens (strange alien-looking creatures) from leg three of the Okeanos Explorer‘s EX1605 expedition.

This cusk eel, found at Unnamed Forearc on June 28th, 2016, was among the first new species discovered during this leg of the expedition.


This ghost-like fish, dubbed “Casper” by land-based scientists, is a species in the fish family Aphonoidae. Until June 30th, 2016, when the ROVs came across Casper, no fish in this family have ever been seen alive.

After a long geology-based dive, the ROVs came upon this undescribed species of Pachycara, commonly called eelpout.

  The scientists wished they had enough time to collect this new species of hard sponge that they discovered on July 6, 2016.

But, they were able to collect this new species of stalked glass sponge!

For more ocean exploration and discoveries be sure to check out the Nautilus Live website for updates from the E/V Nautilus! Situated of  the California coast, the Nautilus is currently (pun intended) mapping and conducting dives off the Channel Islands.

The Okeanos won’t be diving again until June 27th, 2016. Until then, check out dive highlights on our YouTube channel, and the NOAA Ocean Explorer YouTube channel! For more details about individual dives from the NOAA Ship Okeanos Explorer visit the NOAA Okeanos Explorer website.


Images and videos courtesy of the NOAA Office of Ocean Exploration and Research, 2016 Deepwater Exploration of the Marianas.

Okeanos Update: Team Dives Mud Volcanoes

In the Marianas, the west-moving Pacific plate is forced beneath the Philippine plate as they collide, a process known as subduction. As a result, the region is characterized by many geological features including fault lines, earthquakes, volcanoes, cold seeps, hydrothermal vents, and mud volcanoes. Continue reading Okeanos Update: Team Dives Mud Volcanoes

To Boldly Go… Ahyi Seamount

About 12.5 miles off the coast of Farallon de Pajaros, within the Mariana Trench Marine National Monument, lies the Ahyi Seamount, an active underwater volcano. This site remained unexplored until June 22nd, 2016, when the NOAA Ship Okeanos Explorer launched its remotely operated vehicles (ROVs) to investigate the volcano. Continue reading To Boldly Go… Ahyi Seamount

This is what a shark egg looks like?

If you’ve worked at the Inner Space Center for as long as Alex and I have, it’s rare to see something you’ve never seen before during a live dive. The E/V Nautilus is currently studying volcanic activity in the area surrounding the Galapagos Islands, but they stumbled upon a field of what they believe to be shark eggs. As soon as they appeared onscreen, I called the ISC Video Crew into Mission Control to take a look. Continue reading This is what a shark egg looks like?

Investigating an Underwater Volcano

Recently, I joined up with local up-and-coming researcher, Brennan Phillips, on an expedition to the remote waters of the Solomon Islands. At the bottom of this post, you’ll find great article on the work. A huge thank you goes to local legend Todd McLeish for writing the piece.

All images in this article are © Alex DeCiccio. Continue reading Investigating an Underwater Volcano