Magnets: I like to think of them as gravity’s
little cousin. (Really? This guy gonna talk about magnets for 10 minutes?) Well, fine, how about volcanoes? (Yeah, exploding mountains!) Would you have ever guessed that a mere magnet
could dethrone the largest volcano on this planet, possibly even in this solar system!? Oh, magnets just got a lot more interesting,
huh. (yeah cool – when does it blow up?) Okay, stay with me now… That former-king of volcanoes is called Tamu
Massif, and “massif” it is! It sprawls over an area of 120,000 square
miles! For comparison, that’s about the size of
New Mexico, the 5th largest state in the US. Hmm, can’t recall hearing about any volcanoes
the size of an already sizeable state, but maybe I wasn’t paying attention… Oh, it’s an extinct volcano sleeping at
the bottom of the Pacific Ocean 1,000 miles east of Japan. That explains it! Its record-breaking size results partly from
its location, as the volcano sits at the intersection of 3 underwater fault lines. Those, in turn, happen to be part of a larger
system geologists call the Ring of Fire. (Hey, that rings a bell!) Where and how it formed explains why it’s
so ginormous, but I’ll get into that later. For now, what’s with the exotic-sounding
name? It must mean something epic like “Fire Master”
in a language I don’t know. Eh, not quite: “Tamu” is simply an acronym
for Texas A&M University, while “Massif” is a French word used in geology to describe
certain types of mountains based on how they form. It’s also French for “massive” because
what else were they gonna call it? On the long list of famous volcanoes we all
know since grade school (Vesuvius, St. Helens, Fuji, Krakatoa!), why haven’t most people
heard of Tamu Massif? It’s supposedly the largest of them all! The thing is, this sleeping giant hasn’t
erupted in a long looong time. I’m talking 150 million years – back during
the peak of dinosaur times! But just because this volcano has apparently
decided to retire, that doesn’t mean nothing’s happening there. Mainly, it’s a massive source of magnetic
anomalies. That’s the fancy way of saying disruptions
in the Earth’s magnetism. You see, the molten layers beneath the planet’s
crust are rich in metals like iron, nickel, and cobalt. All of those are known for their magnetic
properties. So when you get a whole bunch of them (mmm,
say, 120,000 square miles-worth), you’re bound to produce a magnetic anomaly! Wait, rewind, let’s go back to “molten
layers beneath Earth’s crust.” You might remember hearing about magma back
in school when you were learning about volcanoes and making those cool exploding models. (My class never did that, by the way. I still feel robbed of my childhood to this
day…) Magma is a sort of gooey hot semi-liquid beneath
or within the Earth’s crust. Yep, it’s under your feet right now! (“Oh, ah, hot!”) Since it’s less dense than solid rock, it
naturally flows upward, sometimes finding an exit through a volcano. It might ooze out or explode in a fiery rage
depending on the gaseous pressure behind it. Once a volcano erupts, those magnetically
charged metals (iron, nickel, and cobalt) come to the surface in large amounts. A volcano as big as Tamu Massif is going to
have some outstanding eruptions, especially when it’s in a geological hotspot like the
Ring of Fire. The question that drew many scientists to
the scene was exactly how large these eruptions were and how many there were in all. Enter Dr. William Sager, the marine geophysicist
who discovered the volcano when he was a professor at Texas A&M. When he and his team released the first measurements
of Tamu Massif in 2013, the undersea volcano skyrocketed to the top of the scoreboard. Not only did it dethrone Hawaii's Mauna Loa
as the largest volcano on Earth, it even surpassed Olympus Mons on Mars to become the biggest
known volcano in the Solar System! Well, as far as surface area goes. Impressive for a mountain nobody even knew
existed until recently. Unfortunately for the new reigning champ,
its glory would be short-lived… Back when it won Mount Universe 2013, researchers
were pretty sure a single massive eruption had formed Tamu Massif before the volcano
burned itself out. But like all good scientists, Dr. Sager and
his team wanted to test their theory and make sure. So, they began studying the volcano’s magnetic
anomalies. You see, the Earth’s magnetic field goes
through natural cycles over the course of several million years. You can imagine our planet like a giant magnet. Right now, the North Pole is positively charged,
while the South is negative. That’s why a compass will still point North
even in the Southern Hemisphere. However, the poles will gradually reverse
over millions of years, and lost hikers will be confused to no end! When a volcano erupts, the expelled lava carries
with it the magnetic charge it had when it was part of the earth’s mantle. It also keeps that charge even as the Earth’s
magnetic field continues to shift. By examining these magnetic anomalies, researchers
hoped to get a better understanding of Tamu Massif’s lifecycle. What they found was that this thing isn’t
exactly a volcano… at least not a single one. (Huh?) As the physicist Ricky Ricardo might say:
Let me ‘splain. Originally, they thought it was a regular
shield volcano, only much bigger than any others on this planet. Shield volcanoes form when magma oozes out,
piles up on itself, and cools over time. This forms a giant mound that looks like a
shield lying on the ground, hence the name. The mound would have uniform magnetism throughout
since the magma that spilled up and over would cover it entirely and spread those magnetic
metals out evenly. But that’s not the case with Tamu Massif. It has “stripes” of magnetic anomalies
that point to it popping up a different way. They now think that it’s a sort of volcanic
system formed through seafloor spreading. This is when an ocean ridge spreads apart,
new material forms in the center, and the older stuff goes out to the edges. New material wells up from the middle instead
of being added to the top in the form of dried lava like in shield volcanoes. Tamu Massif’s striped magnetic anomalies
point to gradual seafloor spreading over a couple million years, not volcanic formation
from hardened lava. In short, the crown went back to Hawaii's
Mauna Loa. (Yea!) Tamu Massif is still getting a lot of attention
from geologists. While bulges in the earth’s crust exist
all over, this is the only known example with a massive volcanic system sitting on top! So, Tamu, don’t feel bad about losing your
spot as Earth’s biggest volcano – you’re still one of a kind! (I feel better.) Then again, there are plenty of other volcanoes
that are just as unique and puzzling. Heading over to the Atlantic, geologists recently
found something very exciting just off the shores of Bermuda. All the ships and planes that disappeared
in its infamous triangle? Not exactly, but still just as newsworthy! Most volcanoes in the Caribbean sprang up
along fault lines. You know, just like how the Pacific Plate
is bumping elbows with its neighbors, creating the Ring of Fire. But the undersea volcano that created the
island of Bermuda is well within the North American tectonic plate. Odd, indeed! For many years, geologists assumed that Bermuda
had formed over a volcanic hotspot, just like Hawaii. To prove that long-held theory, scientists
from around the world got together to examine a 2,600-foot sample drilled from the center
of the dormant volcano. What they found ended up being something nobody
had ever seen in this world. Atlantis? If only! They discovered that the island formed due
to unusual activity in what geologists call the Transition Zone. It’s a region of the Earth’s Mantle about
250 miles below sea level. The researchers noticed that the chemical
composition of the rocks resembles those found at that extreme depth. They have much more water and crystalized
minerals than are usually found in the relatively shallower Upper Mantle, which is where most
volcanic magma originates. Because Earth’s molten interior is constantly
shifting, an upwelling occurred around 60 million years ago. That material from the Transition Zone found
itself sucked into the Upper Mantle. From there, the pressure moved it toward the
surface, and the molten rock eventually burned its way through the crust. This phenomenon created a temporary hotspot
from which the volcano, and later the island of Bermuda itself, could form. No one knew that volcanoes could come about
this way. Now that we do know they can, scientists are
scrambling to find more examples of this strange phenomenon. They’re confident that if such an event
could occur once, it must’ve happened before. In fact, it’s likely that many existing
volcanoes have been misidentified as having formed in a more conventional way! Between this and the revelation of Tamu Massif’s
true nature, it’s an exciting time for geologists. Just when you think there’s nothing left
to discover, our world continues to surprise us! Hey, have you ever seen a volcano in real
life? Would you want to? Let me know down below! And if you learned something new today, then
give the video a thumbs up and share it with a friend. But don’t go lava surfing just yet! We have over 2,000 cool videos for you to
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enjoy! Stay on the Bright Side of life!
