WorldAtlas declares Big Island largest island within U.S. territories, and it’s still growing

WorldAtlas, a website dedicated to publishing resources in geography, declared Hawai‘i Island the largest island among the U.S. territories at 4,028 square miles, with the next biggest Kodiak Island off Alaska at 3,588.

Ken Hon, Scientist-in-Charge of the Hawaiian Volcano Observatory, said he never really thought about measuring the size of the Big Island and was surprised that Puerto Rico wasn’t bigger.

But that island located about 1,000 miles off the Florida coast comes in third largest at 3,513 square miles. Rounding out the top 10 are all islands off the coast of Alaska.

Hon said the ocean islands were formed by basaltic volcanoes. Hawai‘i Island encapsulates the cycle of destruction and creation from Mauna Loa, which erupted for the first time in 38 years in 2022, and Kīlauea, which most recently erupted in September and is one of the most continuously active volcanoes in the world.

During the 124-day eruption of Kīlauea in the lower East Rift Zone in 2018, about 8,448 acres of land were consumed, destroying 32.5 miles of public and private roads, covering 700 homes and structures, several farms and public charter school Kua O Ka Lā, according to the observatory.

The eruption forever changed the shape of Pohoiki, a black sand beach along the Puna coastline that Steve Lundblad, a geology professor at University of Hawai‘i at Hilo, described as a once iconic tropical space. Now, it is a bay filled with volcanic debris.

The Big Island is “such a dynamic environment that I think we take for granted because most places on Earth don’t have those dramatic changes,” Lundblad said.

That same eruption also grew the island by 875 acres, equivalent to about 1.36 square miles, creating a new black sand beach along the Puna coastline.

During Kīlauea’s eruption at Puʻuʻōʻō from 1983 to 2018, 437 acres or .68 square miles were added to Big Island.

With the youngest part of the island in Puna, Lundblad said Kohala Mountain is the oldest volcano on the Big Island and it’s the smallest part of the island, with its highest point at 3,500 feet. In comparison, Mauna Loa is 13,769 feet and Kīlauea is 4,091 feet.

The Hawaiian Islands are at the southeast end of a chain of volcanoes that began to form more than 70 million years ago. Each island is made of one or more volcanoes, which first erupted on the floor of the Pacific Ocean and emerged above sea level only after countless eruptions, according to the U.S. Geological Survey.

“A hotspot, a fixed plume of mantle material, formed the islands as the Pacific Plate glided over it, like a stationary piping bag dropping frosting on a rotating cake,” said the WorldAtlas.

But the Big Island of the formed a little less than 500,000 years ago, making it the youngest in the group. It was formed by Mauna Loa, the largest subaerial volcano in mass and volume on Earth, according to the WorldAtlas website. Subaerial volcanoes erupt above the Earth’s surface on land, rather than underwater or beneath ice.

Mauna Loa and Kīlauea are the most active volcanoes in the state. Hualālai volcano, also on the Big Island, is considered active and has erupted three times in the last 1,000 years.

On Maui, Haleakalā last erupted between 400 and 600 years ago. Kama‘ehuakanaloa (formerly Lō‘ihi Seamount), the only known active Hawaiian submarine volcano, erupted most recently in 1996. The volcano’s summit is 3,179 feet below sea level and located 22 miles southeast of the Island of Hawai‘i.

Lundblad said the Hawaiian Islands were formed from a stationary hotspot.

“That ability to have things change so quickly and dramatically is just part of life here,” Lundblad said. “It’s part of the reason why I’m a geologist. I’m interested in the Earth’s changing landscape.”

Malani DeAguiar, a Hawaiian cultural practitioner, said Hawai‘i Island’s size isn’t the only thing that makes it unique. A collective energy encompasses the island, with fire goddess Pele still a resident at Kīlauea.

DeAguiar remembers the first time she heard Madame Pele’s voice, in 1989, while she was a sophomore at the University of Hawai‘i. She went to Kīlauea inside Hawai‘i Volcanoes National Park to pay homage to the fire goddess with her fellow students and professor.

After performing an oli (chant) toward the glowing crater, DeAguiar’s professor asked if she heard Pele answer. DeAguiar chanted again. As she ended, she listened and heard crackling.

“That is Pele thanking you,” DeAguiar recalled her professor saying.

Last year, DeAguiar went to Kīlauea to again pay homage to Pele with an oli.