SCIENCE

There’s a new island in the Pacific Ocean, thanks to the eruption of an underwater volcano. (Popular Science)

Take a look at Hunga Tonga’s before-and-after geography with this fun interactive slider!

Teachers, scroll down for a quick list of key resources in our Teachers’ Toolkit, including a link to today’s MapMaker Interactive map.

Discussion Ideas

• Read through “Geology of the Deep,” our terrific 2013 article on submarine volcanoes—or just skip to the article’s “World’s Youngest Island” section. According to the article, one of the world’s newest volcanic islands was created by the eruption of Hunga Tonga in 2009. But the Popular Science article says that Hunga Tonga just created the new island in 2015. How does this make sense?
  • The 2009 island was mostly made of volcanic ash and eroded into the ocean fairly quickly. Volcanologists expect the new island, too, to erode in a matter of months. As Popular Science says: Temporary Geography.
  • The two islands that bracket the series of temporary islands, Hunga Tonga and Hunga Ha’apai, are permanent. Take a closer look at them in the first bookmark in today’s MapMaker Interactive map. Be sure to click on the “i” marker for more information!

 

• Our article says that submarine volcanoes form as a result of tectonic activity. Which tectonic plates are involved in the eruption of Hunga Tonga? Take a look at the second bookmark (“Tectonic Activity”) in today’s map for some help!
  • Hunga Tonga lies near the Kermadec-Tonga Trench, where the mighty Pacific plate is interacting with the Australian plate.

 

• Take a look at the diagram above, showing different ways tectonic plates interact. What sort of tectonic activity do you think is taking place near Hunga Tonga?
  • Subduction, our favorite geologic phenomenon! Subduction occurs at convergent tectonic boundaries where a massive tectonic plate—and no plate is more massive than the Pacific!—sinks or melts beneath a less-massive plate.
  • Trenches and volcanic arcs are usually good indicators of subduction zones—just take a look at the third bookmark in today’s map (“Aleutians”) about 13,000 kilometers (8,000 miles) north of Hunga Tonga. For more information, take a look at our encyclopedic entry on volcano or consult this beautiful 1985 map of “Earth’s Dynamic Crust.”
  • FYI: Both Hung Tonga (bookmark 2) and the Aleutian Islands (bookmark 3) are part of the “Ring of Fire” (bookmark 4) an incredibly active string of volcanoes that limns the Pacific Ocean.

 

TEACHERS’ TOOLKIT

Popular Science: An Underwater Volcano Just Created a New Island

Nat Geo: Geology of the Deep

Nat Geo: Hunga Tonga map series

Airbus: Eruption of a volcano in the Tonga archipelago

Smithsonian Institution: Global Volcanism Program: Hunga Tonga-Hunga Ha’apai

Nat Geo: What is a volcano?