Malumalu facts for kids

Malumalu is a special kind of underwater mountain called a seamount. It's located in American Samoa, which is a group of islands in the Pacific Ocean. Malumalu is part of a bigger underwater landscape that includes the islands of Savaii, Upolu, and Tutuila.

This seamount sits quite close to a very deep part of the ocean called the Tonga Trench, which is about 100 kilometers (62 miles) to the south. Malumalu is also about 66 kilometers (41 miles) south of Ofu island. Sometimes, people call Malumalu the "Southeast Bank."

What is Malumalu?

Malumalu is actually a young volcano that is mostly hidden underwater. It's found at the eastern end of a chain of volcanoes that starts near Tutuila island. Scientists have named this chain the "Malu trend."

Volcano Chains

The "Malu trend" is different from another chain of volcanoes nearby called the "Vai Trend." The Vai Trend includes islands like Ofu, Ta'u, and the active underwater volcano Vailulu'u. These volcano chains are similar to famous ones in Hawaii, like the "Kea" and "Loa" trends, which also show how volcanoes form over time.

Malumalu is not much older than Vailulu'u. Vailulu'u has even erupted in recent times, which means it's still very active!

How Old is Malumalu?

Scientists study the rocks from Malumalu to learn about its past. They look at special elements in the rocks to figure out when volcanic eruptions happened. Their studies show that Malumalu has had at least three big volcanic events in the last 300,000 years. Two of these happened in the last 150,000 years, and at least one eruption was as recent as 8,000 years ago. This tells us that Malumalu has been active for a long time!

The Samoa Hotspot

Malumalu is part of what scientists call the Samoa hotspot. A hotspot is a place deep inside the Earth where hot rock, called a mantle plume, rises up. This hot rock melts and creates volcanoes on the surface, or in this case, under the ocean.

Future of Malumalu

Scientists have a model that helps them understand how the Samoa hotspot works. This model suggests that the volcanic activity at Malumalu will slowly decrease over the next 10,000 to 100,000 years. This is because the hot mantle plume is slowly being pushed northeast towards Vailulu'u. This movement is caused by the way the Earth's deep layers, like the Tonga slab, are moving. So, while Malumalu has been active, its volcanic days might be slowing down in the distant future.