Tamu Massif

Have you ever searched for something that you felt like you would never find? Maybe you lost your cellphone or you swear that your favorite t-shirt is hiding from you. You search every corner of your home, tear open drawers, and look under the bed, but you still can’t find it. When you eventually find the item, you realize it was right in front of you the whole time.

For centuries, humans have wondered what generates Earth’s internal energy and how it affects the planet’s surface. Scientists have been formally investigating Earth’s interior and volcanic activity around the world for decades. They constantly look for anomalies and unique features that no one has ever discovered. Sometimes it feels like parts of Earth are hiding from scientists, just like your lost cellphone hides from you.

A detailed map shows the topography throughout the Pacific Ocean, where Tamu Massif is located.
(Will Sager/Schmidt Ocean Institute)

The world’s largest volcano has been hiding from us for millions of years underneath the depths of the ocean. How did one of the largest geological features in our solar system go unnoticed for so long?

This volcano, named Tamu Massif, was discovered and researched by a scientist named William Sager. “Tamu” is an abbreviation of Texas A&M University, where Sager worked for 29 years, and “Massif” comes from the French word for massive.

Tamu Massif is located about 1,000 miles east of Japan. The 145 million year old volcano lies about 1,981 meters (6,500 feet) under the ocean’s surface. Though Hawaii’s Mauna Loa volcano stands taller than Tamu Massif, Tamu spans an area nearly 50 times larger.

Scientists developed a detailed 3D map of the seafloor shape, revealing features of the world's largest single volcano.
(Will Sager/Schmidt Ocean Institute)

Tamu Massif has a very gentle slope, meaning that it is not tall, but extremely wide. It is categorized as a shield volcano because the gentle slope and dome-shape make it look like a giant shield protruding from the ground.

Studying this volcano, and many of Earth’s underwater features, is challenging because it lies in the dark depths of the ocean. Sager and his research team have delved these depths, discovering more about the formation of seafloor structures.

To study Tamu Massif, the team used sonar and magnetic fields to create maps of the ocean floor with considerable detail. Using this data, the scientists create 3D maps that allow us to look at what was once hidden underneath the ocean.

This information reveals that Tamu Massif formed when an enormous amount of magma rose up from Earth’s mantle. Tamu Massif sits at a unique boundary of three tectonic plates. Magma rose up through the particularly thin crust at this intersection, cooled, and created new rock to form this extraordinary volcanic mass.

A segment of the detailed mapping of Tamu Massif shows a basal escarpment, or long cliff, on the volcano.
(Will Sager/Schmidt Ocean Institute)

Instruments, like this magnetometer, were damaged by sharks as scientists researched Tamu Massif.
(Will Sager/Schmidt Ocean Institute)
Sharks were attracted to the magnetic fields of "Maggie" the magnetometer, which scientists used to collect magnetic data about Tamu Massif.
(Will Sager/Schmidt Ocean Institute)
Shark interference with the scientific instruments posed a challenge for scientists studying Tamu Massif.
(Brian J. Skerry/National Geographic Creative)
Scientists studying Tamu Massif used technology to reveal what was hiding underneath the surface of the ocean.
(Will Sager/Schmidt Ocean Institute)
Scientists dropped instruments into the depths of the Pacific Ocean to discover more information about Tamu Massif, the volcano's structure, and how it formed.
(Will Sager/Schmidt Ocean Institute)

Sometimes scientists encounter unexpected obstacles while conducting research. In this case sharks interfered! It turns out the magnetometers, a tool that the scientists used to map the volcano, emitted magnetic fields that attracted sharks. The sharks bumped, moved, and damaged many of the devices. But, the researchers worked around the sharks in order to show the world something new and exciting.

Uncovering Tamu Massif as one of Earth’s hidden wonders opens many doors. Continued studies of Tamu Massif and similar ocean floor features will help to support scientists’ knowledge of plate tectonics and potentially reveal even more mysteries.

A 3D map reveals the tremendous size of Tamu Massif and the geological features surrounding the volcano.
(Will Sager/Schmidt Ocean Institute)

PLATE BOUNDARIES

Tamu Massif

A Giant in the Deep

Tamu Massif

The Mid-Atlantic Ridge

San Andreas Fault

Maar Volcanoes

Fire Under the Ice

Yellowstone