The Hawaiian Islands form a volcanic archipelago built up over millions of years. The island chain exhibits a clear age progression: islands become progressively older and more eroded the farther they are located from the southeast. This systematic change provides a geological timeline for the formation of the islands and determines which island currently holds the title of the youngest.
The Hotspot That Creates the Chain
The existence of the Hawaiian Islands is a direct consequence of a stationary mantle plume, or hotspot, located deep beneath the Pacific Plate. This plume of hot material rises from the Earth’s mantle, causing the overlying rock to melt and form magma. The magma then punches through the crust to create volcanoes on the seafloor.
The Pacific Plate is constantly moving in a west-northwesterly direction across the fixed hotspot. As the plate slowly shifts, a new volcano begins to form over the plume, while the older volcano is carried away. This process leaves a trail of volcanic islands and submerged seamounts that increase in age toward the northwest, a progression spanning over 6,100 kilometers (3,800 miles) and including the Emperor Seamounts. The sustained activity of the hotspot ensures that the southeastern-most part of the chain is always the location of the newest volcanic activity.
Naming the Youngest Hawaiian Island
The youngest island that has emerged above sea level in the Hawaiian chain is Hawaiʻi Island, commonly known as the Big Island. This island is currently situated directly over the mantle hotspot, which fuels its continued volcanic growth. The island is a composite of five major shield volcanoes, including the largest on Earth, Mauna Loa, and the most active, Kīlauea.
The ongoing and frequent eruptions of Kīlauea are the most visible evidence of the island’s youth, continually adding new land. About 90 percent of Kīlauea’s surface is covered with lava flows less than 1,100 years old. Mauna Loa, the other active giant, last erupted in 2022, demonstrating that the island’s construction is far from complete. Its southeastern position and current state of active volcanism confirm its status as the youngest landmass in the visible archipelago.
The volcanoes of Hawaiʻi Island are still in the shield-building stage, characterized by massive outpourings of fluid lava that create the broad, gently sloping shield shape. This stage is the most voluminous in a Hawaiian volcano’s life cycle. Mauna Loa began producing shield-stage lavas between 600,000 and one million years ago, and Kīlauea transitioned into this stage about 155,000 years ago. This continuous growth contrasts sharply with the older, dormant, and heavily eroded islands farther up the chain, such as Kauaʻi, whose volcanism ended millions of years ago.
The Island That Has Not Yet Appeared
While Hawaiʻi Island is the current youngest landmass, the next volcano in the chain is already growing beneath the waves. This future island is the Kamaʻehuakanaloa Seamount, formerly known as Lōʻihi, which is an active submarine volcano located about 35 kilometers (22 miles) off the southeast coast of Hawaiʻi Island. Kamaʻehuakanaloa is the youngest volcano in the entire Hawaiian Ridge, representing the earliest, or preshield, stage of volcanic development.
The seamount’s summit is currently about 975 meters (3,200 feet) below the ocean surface. Seismic data, including a notable swarm of over 4,000 earthquakes in 1996, indicates that the volcano is actively building. Based on the growth rates of previous Hawaiian volcanoes, Kamaʻehuakanaloa is expected to breach the surface and become the next island in the chain sometime between 10,000 and 100,000 years from now.