News
Underwater Volcano is the Largest in the World – Comparable in Size to Olympus Mons on Mars
A giant volcano the size of New Mexico or the British Isles has been found under the Pacific Ocean, about 1,000 miles (1,600 kilometers) east of Japan, making it the biggest volcano on Earth and one of the biggest in the solar system.
Called Tamu Massif, the giant shield volcano had been thought to be a composite of smaller structures, but now scientists say they must rethink long-held beliefs about marine geology.
“This finding goes against what we thought, because we found that it’s one huge volcano,” said William Sager, a geology professor at the University of Houston in Texas. Sager is lead author in a study about the find that was published this week in the peer-reviewed journal Nature Geoscience.
“It is in the same league as Olympus Mons on Mars, which had been considered to be the largest volcano in the solar system,” Sager told National Geographic.
Tamu Massif is a rounded dome that measures about 280 by 400 miles (450 by 650 kilometers), or more than 100,000 square miles. Its top lies about 6,500 feet (about 2,000 meters) below the ocean surface, while the base extends down to about 4 miles (6.4 kilometers) deep. Tamu Massif dwarfs the largest active volcano on Earth, Mauna Loa in Hawaii, which measures about 2,000 square miles (5,200 square kilometers).
Made of basalt, Tamu Massif is the oldest and largest feature of an oceanic plateau called the Shatsky Rise in the northwestern Pacific Ocean. The total area of the rise is similar to Japan or California.
Sager started studying Tamu Massif about 20 years ago. He named it Tamu Massif because Tamu is short for Texas A&M University, where the scientist worked at the time; massif is French for “massive” and is a scientific term for a large mountain.
Scientists had known about the Shatsky Rise since the early 20th century, when it was first mapped, he explained. “We knew it was a big mountain range, but we didn’t know what the structure was like or how it formed,” said Sager.
He added that Tamu Massif is different from classic seamounts, the volcanoes that protrude off the ocean floor around the world by the tens of thousands. Tamu Massif is much larger, with a much more gentle slope than classic seamounts, Sager said.
Near the summit of Tamu Massif, the slope is only around one degree, he said. Down the flank the slope is half a degree, and it’s even less than that near the base. (The average slope of a staircase is 40 degrees, and an easy ski slope is about 10 degrees.) ”If you were standing on the massif, you would have a hard time knowing which way is down,” said Sager.
Finding an Unusual Structure
Scientists had thought the giant Shatsky Rise formed over time as a composite of several volcanoes that grew together, in a process similar to the way the big island of Hawaii was made by the outpourings of five separate volcanoes that were in close proximity.
But when Sager and colleagues looked at seismic data of Tamu Massif, they were surprised at what they found.
“We saw what appear to be lava flows going out from the center of the volcano in all directions, with no obvious large secondary source of volcanism, so that was a surprise,” Sager said.
The team also performed geochemical analysis on core samples taken from the massif. They found that the huge structure appeared to be made out of the same rock, of the same age.
So the scientists concluded that Tamu Massif was created by a single volcano, and probably over a relatively short period of time of a few million years. The volcano went “extinct,” meaning inactive, shortly after it formed, Saged added. That was probably in the Late Jurassic to Early Cretaceous period, about 145 million years ago.
“If what they are saying is correct, that is truly a massive volcano,” said Brian Jicha, a geologist at the University of Wisconsin who has received funding from National Geographic to study the formation of the Aleutian Islands.
“There are a lot of these oceanic plateaus, so if some of them really are just volcanoes, this paper might begin to change the way we think oceanic plateaus are built, and maybe even some of the continental basalt plateaus,” said Jicha, who was not involved in the study.
Sager agrees that more work is needed on other oceanic plateaus. “There could be around a dozen of these things out there,” he said about the possibility of more large shield volcanoes under the sea.
Sager noted that although Tamu Massif currently appears to be the largest single volcano on Earth, there are still larger volcanic complexes, such as theSiberian Traps, which may hold other mysteries. Those features were likely made up of molten rock from different sources, he said, unlike Tamu Massif’s formation according to the new theory.
How Did the Volcano Form?
Sager said scientists are still trying to work out the details of how Tamu Massif formed.
He said it seems likely that the spot on the seafloor had the right mix of elements, including a boundary of three tectonic plates, thin crust, and a source of hot magma below that was able to bubble up to the surface. The molten rock poured out, and then built up a wide, gradual rise as it cooled.
Precisely how the magma made it to the surface is an open question. Perhaps a blob of the rock got superheated, and then rose to the surface due to buoyancy. Or, cracks in the overlying crust could have opened, allowing molten rock to spill out.
The next step will be more work to figure out what the source of the magma was, said Sager. He would like to go back and measure the magnetic properties of the rock, using a ship that is equipped with GPS. The data will give him a better idea how the lava spread out, he said.
Jicha added that “if it is indeed really one volcano, and the case is fairly compelling, the amount of magma that had to go through the lithosphere [crust] is off the charts.”
“Not only does [Tamu Massif] give us a new wow in the form of a giant new volcano, but it gives us new insight into a building block of an oceanic plateau,” said Sager.
He’s not sure if the new volcano will help scientists better understand Olympus Mons on Mars, but noted that “we can see the surface of Mars better than we can see the bottom of the ocean.”
Tamu Massif, he said, “has been hiding out for 145 million years because it found a good place to hide.”
Source: National Geographic
Jake Davies boards Ghazala Explorer for an unforgettable Red Sea diving experience…
Overnight, the wind picked up, making the planned morning dive a bit bumpy on the Zodiacs to the drop point on Thomas Reef. There, we would dive along the reef before descending through the canyon and then passing under the arch before ascending the wall with a gentle drift. The site provided great encounters with more pelagic species, including shoals of large barracuda, tuna, and bigeye trevally.
Once back on the boat, it was time to get everything tied down again as we would head back south. This time, with the wind behind us, heading to Ras Mohammed to dive Jackfish Alley for another great gentle drift wall dive before then heading up the coast towards the Gulf of Suez to moor up at the wreck of the Thistlegorm. This being the highlight wreck dive of the trip and for many onboard, including myself, it was the first time diving this iconic wreck. I had heard so much about the wreck from friends, and globally, this is a must on any diver’s list. Fortunately for us, there was only one other boat at the site, which was a rarity. A great briefing was delivered by Ahmed, who provided a detailed background about the wreck’s history along with all the required safety information as the currents and visibility at the site can be variable.
Kitting up, there was a lot of excitement on deck before entering the water and heading down the shoreline. Descending to the wreck, there was a light northerly current which reduced the visibility, making it feel more like the conditions that can be found off the Welsh coast. At 10m from the bottom, the outline of the wreck appeared as we reached the area of the wreck which had been bombed, as our mooring line was attached to part of the propeller shaft. Arriving on deck, instantly everywhere you looked there were many of the supplies which the ship was carrying, including Bren Carrier tanks and projectiles that instantly stood out.
We headed around the exterior, taking a look at the large propeller and guns mounted on deck before entering the wreck on the port side to take a look in the holds. It was incredible to see all the trucks, Norton 16H, and BSA motorcycles still perfectly stacked within, providing a real snapshot in time.
Overall, we had four dives on the Thistlegorm, where for all of the dives we were the only group in the water, and at times, there were just three of us on the whole wreck, which made it even more special, especially knowing that most days the wreck has hundreds of divers. Along with the history of the wreck, there was plenty of marine life on the wreck and around, from big green turtles to batfish, along with shoals of mackerel being hunted by trevally. Some unforgettable dives.
The final leg of the trip saw us cross back over the Suez Canal to the Gobal Islands where we planned to stay the night and do three dives at the Dolphin House for the potential of sharing the dive with dolphins. The site, which included a channel that was teeming with reef fish, especially large numbers of goatfish that swam in large shoals along the edge of the reef. These were nice relaxing dives to end the week. Unfortunately, the dolphins didn’t show up, which was okay as like all marine life they are difficult to predict and you can’t guarantee what’s going to be seen. With the last dive complete, we headed back to port for the final night where it was time to clean all the kit and pack before the departure flight the next day.
The whole week from start to finish on Ghazala Explorer was amazing; the boat had all the facilities you need for a comfortable week aboard. The crew were always there to help throughout the day and the chefs providing top quality food which was required after every dive. The itinerary providing some of the best diving with a nice mixture of wreck and reef dives. I would recommend the trip to anyone, whether it’s your first Red Sea liveaboard in the Red Sea or you’re revisiting. Hopefully, it’s not too long before I head back to explore more of the Red Sea onboard Ghazala Explorer.
To find out more about the Northern Red Sea reef and wrecks itineraries aboard Ghazala Explorer, or to book, contact Scuba Travel now:
Email: dive@scubatravel.com
Tel: +44 (0)1483 411590
Photos: Jake Davies / Avalon.Red
Jake Davies boards Ghazala Explorer for an unforgettable Red Sea diving experience…
The second day’s diving was a day full of wreck diving at Abu Nuhas, which included the Chrisoula K, Carnatic, and Ghiannis D. The first dive of the day was onto the Chrisoula K, also known as the wreck of tiles. The 98m vessel remains largely intact where she was loaded with tiles which can be seen throughout the hold. The stern sits at 26m and the bow just below the surface. One of the highlights of the wreck is heading inside and seeing the workroom where the machinery used for cutting the tiles are perfectly intact. The bow provided some relaxing scenery as the bright sunlight highlighted the colours of the soft coral reef and the many reef fish.
Following breakfast, we then headed to the next wreck, which was the Carnatic. The Carnatic is an 89.9m sail steamer vessel that was built in Britain back in 1862. She ran aground on the reef back in 1869 and remains at 27m. At the time, she was carrying a range of items, including 40,000 sterling in gold. An impressive wreck where much of the superstructure remains, and the two large masts lay on the seafloor. The wooden ribs of the hull provide structures for lots of soft corals, and into the stern section, the light beams through, bouncing off the large shoals of glass fish that can be found using the structure as shelter from the larger predators that are found outside of the wreck.
The final wreck at Abu Nuhas was the Ghiannis D, originally called ‘Shoyo Maru,’ which was 99.5m long and built in Japan back in 1969 before becoming a Greek-registered cargo ship in 1980. The ship then ran aground on the reef on April 19th, 1983, and now sits at the bottom at a depth of 27m. Heading down the line, the stern of the ship remains in good condition compared to the rest of the hull. The highlight of the wreck, though, is heading into the stern section and down the flights of stairs to enter the engine room, which remains in good condition and is definitely worth exploring. After exploring the interior section of the ship, we then headed over to see the rest of the superstructure, where it’s particularly interesting to see the large table corals that have grown at the bow relatively quickly considering the date the ship sank. After surfacing and enjoying some afternoon snacks, we made sure everything was strapped down and secured as we would be heading north and crossing the Gulf of Suez, where the winds were still creating plenty of chop.
The next morning, it was a short hop to Ras Mohammed Nature Reserve for the next couple of days of diving. The 6am wake-up call came along with the briefing for the first site we would be diving, which was Shark & Yolanda. The low current conditions allowed us to start the dive at Anemone City, where we would drift along the steep, coral-filled wall. These dives involved drifts, as mooring in Ras Mohammed wasn’t allowed to protect the reefs. As a dive site, Shark & Yolanda is well-known and historically had a lot of sharks, but unfortunately not so many in recent years, especially not so early in the season. However, there was always a chance when looking out into the blue.
The gentle drift took us along the steep walls of the site, with plenty of anemone fish to be seen and a huge variety of corals. It wasn’t long into the dive before we were accompanied by a hawksbill turtle, who drifted with us between the two atolls before parting ways. Between the two reefs, the shallow patch with parts of coral heads surrounded by sand provided the chance to see a few blue-spotted stingrays that were mainly resting underneath the corals and are always a pleasure to see. With this being the morning dive, the early sunlight lit up the walls, providing tranquil moments. Looking out into the blue, there was very little to be seen, but a small shoal of batfish shimmering underneath the sunlight was a moment to capture as we watched them swim by as they watched us.
Towards the end of the dive, we stopped at the wreck of the Jolanda where the seafloor was scattered with toilets from the containers it was carrying. This provided a unique site to make a safety stop, which was also accompanied by a large barracuda slowly swimming by, along with a hawksbill turtle calmly swimming over the reef as the sun rays danced in the distance.
For the next dive, we headed north to the Strait of Tiran to explore the reefs situated between Tiran Island and Sharm El Sheik, which were named after the British divers who had found them. We started on Jackson before heading to Gordons Reef, where we also did the night dive. All the atolls at these sites provided stunning, bustling coral reefs close to the surface and steep walls to swim along, which always provided the opportunity to keep an eye out for some of the larger species that can be seen in the blue. Midwater around Jackson Reef was filled with red-toothed triggerfish and shoals of banner fish, which at times were so dense that you couldn’t see into the blue. Moments went by peacefully as we enjoyed the slow drift above the reef, watching these shoals swim around under the mid-afternoon sun.
The night dive at Gordon’s Reef was mainly among the stacks of corals surrounded by sand, which was great to explore under the darkness. After some time circling the corals, we came across what we were really hoping to find, and that was an octopus hunting on the reef. We spent the majority of the dive just watching it crawl among the reef, blending into its changing surroundings through changes in colour and skin texture. It’s always so fascinating and captivating to watch these incredibly intelligent animals, in awe of their ability to carry out these physical changes to perfectly blend into the reef. Before we knew it, it was time to head back to the boat to enjoy a well-deserved tasty dinner prepared by the talented chefs onboard.
Check in for the 3rd and final part of this series from Jake tomorrow!
To find out more about the Northern Red Sea reef and wrecks itineraries aboard Ghazala Explorer, or to book, contact Scuba Travel now:
Email: dive@scubatravel.com
Tel: +44 (0)1483 411590
Photos: Jake Davies / Avalon.Red
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