NASA scientists pay first visit to the volcanic island in Tonga so new it is not on any map



February 6, 2019 10:33:08

Scientists from Nasa made their first visit to an island that rose from the sea from the edge of the Hunga Tonga Hunga Ha 'apai volcano in Tonga when it erupted in 2015.

Key points:

  • The island was formed three years ago, has no name and was not expected to last so long
  • Scientists and visiting students have found an unusual, sticky, light-colored mud.
  • They collected data to help them understand how they withstood erosion for so long

The island, which has no official name and which Goddard Space Flight Center researcher Dan Slayback previously had only seen from space, is nestled between two of the oldest islands in the South Pacific nation.

Slayback joined scientists and students of the Sea Education Association who traveled by boat to the island in early October 2018.

When they landed, they found a kind of sticky, unexpected mud, plants beginning to settle, probably strewn with bird droppings, hundreds of nesting birds – and a barn owl.

"We were all like happy kids," Slayback said.

"The maximum of [the island] is this black gravel, I will not call it gravel the size of a sand, "he said.

"And then there's clay washing out [volcano’s] cone.

"In satellite imagery, you see this light-colored material. It's mud, that mud-colored mud.

"It's very sticky, so even if we had seen it, we really did not know what it was, and I'm still a bit confused where it's coming from, because it's not gray."

Plants starting to take root in new soils

The group photographed the new vegetation growing on an isthmus connecting the island to one of its neighbors, some of which possibly growing from bird droppings.

They also saw a barn owl, which probably flew from one of the neighboring islands, and hundreds of nested cliffs around the island's crater lake.

During his visit, Mr. Slayback collected small samples of rocks for analysis in NASA labs, and attempted to calculate the actual elevation of the island.

He and his students used a GPS unit to make accurate location measurements and a drone to complete an aerial survey to help create a higher resolution 3D map of the island.

"It really surprised me how valuable it was to be there personally for some of these things. It really makes clear to you what's going on with the landscape," he said.

Being there personally enabled a better observation and understanding of the deep ravines running alongside the cone of the island.

"The island is wearing out in the rain much faster than I imagined," Slayback said.

"We focus on erosion on the south coast, where the waves are collapsing, which is happening. It's just that the whole island is sinking too.

"It's another aspect that gets very clear when you are facing huge erosion ravines," he said.

"That was not here three years ago and now it's two feet deep."

Island was never expected to last this long

When it rose from the Pacific Ocean in early 2015, after the Hunga Tonga Hunga Ha 'apai volcano erupted, throwing rocks and lava in the sky, scientists did not expect the land mass to last.

But three years later it is still standing – and, according to NASA, is one of only three islands formed by volcanic eruptions in the last 150 years that have survived for more than a few months.

While "there is no map of the new earth," according to Mr. Slayback, he and his colleagues have been watching from their satellites since birth to try to understand why it has not yet been washed.

Since the visit, Mr. Slayback has used the data collected on the island to create a more realistic 3D model of the site.

This will help scientists better understand its volume, and how much material and volcanic ash came up during its creation.

Mr. Slayback is also planning another visit to Tonga to help answer questions about the seabed around the island.

This could help scientists better understand why so far it has been partially resistant to erosion – and why it has survived so far.


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Science and technology,

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