The vast majority of the landmass in the world sits on continental crust, but the Hawaiian Islands are an exception. The Hawaiian Islands owe their existence to volcanoes - they are basically the tops of massive volcanic mountains poking above the ocean surface.
The pattern of the Hawaiian Islands forming a chain of islands running to the northwest is for a particular reason. The islands of Hawaii are located above the Hawaiian hotspot - it is a volcanic hotspot that is responsible for the massive 6,200-kilometer (3,900 mi) Hawaiian-Emperor seamount chain. Most of the chain is underwater. It extends from the island of Hawaii to near Russia at the edge of the Aleutian Trench.
What The Hawaiian Hotspot Is
The hotspot is a plume of magma—molten rock—puncturing Earth’s crust and extending hundreds of kilometers below Earth’s surface.
The Hawaii Hotspot is one of the most intensively studied hotspots in the world. It is known to have four active volcanoes, two dormant volcanoes, and over 123 extinct volcanos. Many of these are not atolls or seamounts.
Volcanoes Status:
- Active: 4 Active Volcanoes
- Dormant: 2 Dormant Volcanoes
- Extinct: 123 Extinct Volcanoes (At Least)
As the plate slides over the hotspot the volcanoes move passed it. They then become extinct and weathered and eventually erode back into the ocean. New volcanoes form as new crust moves over the hotspot.
The Hawaiian Hotspot is now known to be 500 to 600 km (310 to 370 mi) wide and up to 2,000 km (1,200 mi) deep. It is thought to have been active for at least 70-85 million years and the chain's rate of drift has slowly been increasing over time. This acceleration has decreased the amount of time each volcano spends over the hot spot.
- Hawaiian-Emperor Chain: 6,200-kilometer (3,900 miles) Long
- Age: The Hot Spot Is 70-85 Million Years Old
- Movement: Around 7 cm or 2.75 Inches Per year
While the 76 million-year-old Detroit Seamount is thought to have spent 18 million years over it, one million-year-old Kohala has only spent 900,000 years over it. At the same time, the volcanoes have become more active while over the hotspot.
- Amount Of Lava Erupted: 186,000 Cubic Miles
An effect of this is creating quickly-silenced, closely spaced volcanoes overlapping each other forming superstructures as Hawaii island. The amount of lava that has been erupted over the life of the Hawaiian Hotspot is enough to cover the State of California with a layer 1 mile thick.
Notable Volcanoes Of The Hotspot
The mountains are giants - but most of them are not visible as they are underwater. Some are over 30,000 feet above the seafloor. They are just the tips of the proverbial icebergs. So much so that if they were to be measured from their base in the ocean and for the island of Hawaii to be considered "mountain" then they would be the world's tallest.
- Active Volcanoes: Kilauea, Mauna Loa, Hualalai, Haleakala, and Kama‘ehuakanaloa (submarine)
Mauna Kea Volcano has an altitude of 13,796 feet - but its base is around 18,000 feet below sea level, taken together it is over 1,000 feet taller than Mount Everest.
- Mauna Kea Volcano: Can Be Thought Of As Taller Than Mount Everest
- Kīlauea: The Youngest And Most Active Volcano
- Mauna Loa: The Largest Volcano On Earth
- Hualālai: The Third Most Active Volcano On The Island of Hawaii
- Kama‘ehuakanaloa: (formerly Lō‘ihi Seamount) The Only Known Active Hawaiian Submarine Volcano
- Haleakalā: The Only Active Volcano On Island of Maui
These are some of the most impressive volcanoes in the world - Iceland is another hotspot and also boasts awe-inspiring volcanoes.
Future Of Hawaii - The New Island of Loihi
Big Island is the youngest of the islands and that is where volcanic activity is still occurring. Eruptions are occurring on the island's southern shore.
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- Oldest Island: Kauai Is The Oldest of The Hawaiian Islands
- Youngest: Big Island Is The Youngest of The Hawaiian Islands
Kauai is the oldest of the islands and is no longer over the hotspot and so no longer has any active volcanoes. Kilauea isn’t the only volcano on the Big Island. There are also Kohala, Mauna Kea, Hualalai, and Mauna Loa. Of these four volcanoes, only Hualalai and Mauna Loa are active. Two of these active volcanoes are in the stunning Hawai'i Volcanoes National Park.
Eventually, Hawaii will be joined by another island called Loihi. This future island has already grown by thousands of meters (yards), but it is still roughly 1,000 meters (3,280 feet) below the surface of the Pacific Ocean. Scientists believe it will emerge between 10,000 to 100,000 years from now.
- Loihi: The Future Island That Will Emerge Between 10,000 and 100,000 Years From Now
- Depth: The Future Island Is Still around 1,000 meters (3,280 feet) Below The Surface