American Oceans

How Paradise Began: The Formation of Hawaii

If you have ever considered a tropical island getaway, Hawaii has probably crossed your mind. This popular tourist destination has some of the most breathtaking sites in the world. 

hawaii na pali paradise island formation

From the crystal clear Pacific Ocean, the coral reefs, the scenic hikes, and incredible sunsets, it’s no wonder why people continue to flock to Hawaii and its islands.

How Was Hawaii Formed?

Have you ever wondered how these islands came to be? If so, you’re not alone. The most commonly taught answer, though insufficient, is that the islands were formed from volcanic activity. 

hawaii island in front of beautiful sunset formed

While it is true that volcanoes played a significant role in the formation of this island chain, there is far more to the story of the Hawaiian islands. So, how did Hawaii become the paradise that we all know and admire today?

How Many Islands Does Hawaii Have?

When you think of the Hawaiian islands, the names Maui, Oahu, and Hawaii (sometimes known as the ‘Big Island’), likely spring to mind. 

hawaii islands map showing maui oahu and other

While these are three of the largest and most popular islands in the chain, there are, in fact, five other major Hawaiian islands. The names of these islands are Kohhlawe, Lanai, Molokai, Kauai, and Niihau.

Of these eight major islands, seven of them are inhabited. Niihau is the only major island in Hawaii that is not regularly occupied as it is privately owned. 

You might be surprised to learn that there are over 100 islands in this archipelago. There are 137 Hawaiian islands, to be exact, each with unique attractions and geology.  

Hawaii has Volcanic Origins

Approximately 40 to 70 million years ago, the 137 islands of Hawaii began to form. Every island in the archipelago originated from multiple underwater volcanic eruptions. 

hawaii island origins from multiple volcanic eruptions

Magma burst from underneath the seafloor until it reached the ocean’s surface. Once magma reaches the Earth’s surface, it is known as lava.

Lava cools and solidifies to form landmasses, or islands. Due to their volcanic origins, it is not surprising that all of the islands in this chain have at least one volcano.

Some of the islands, like the Big Island of Hawaii, have more than one. Most of the islands’ volcanoes have not erupted in years and are considered dormant. 

There are currently only six active volcanoes in Hawaii, with four on Hawaii and two on Maui. The newer islands are where you’ll find active volcanoes.

Mauna Loa is the largest active volcano on Earth. You’ll find it standing over 9,000 feet on the island of Hawaii. 

Hawaii is a Geologically Unique Location

Hawaii is unlike any other place on Earth because of the way it formed, but also because of its location.

hawaii hot spot geologically underneath unique underwater location

Volcanic eruptions caused the formation of the Hawaiian islands, but these eruptions originated from a hot spot underneath the seafloor. 

Heat rises from deep in the Earth’s mantle, creating underwater volcanoes. Eventually, as these volcanoes continue to erupt, the magma will reach the Earth’s surface and form land. 

Hot spots are unique places because they’re usually not found at the boundaries of tectonic plates where we are used to seeing volcanoes form.

Most of the world’s active volcanoes are located in the Ring of Fire and on the Pacific tectonic plate’s boundaries. 

Scientists estimate that there are only 40 to 50 hot spots in the world. These include the hot spots that formed Hawaii and caused geysers in Yellowstone National Park. 

The Formation of the Islands

The question remains; how was Hawaii formed? The formation of Hawaii is clearly more complex than simply attributing it to volcanoes.

volcanoes in formation of hawaii islands

The Pacific tectonic plate was, and still is, moving northwest across the hot spot under the seafloor.

As this plate moved across the hot area where magma forms, a volcano pushed the magma through the plate to the Earth’s surface.

When the magma hit the Earth’s surface, it became lava. That lava eventually solidified. This process may technically be how the islands came to be, but it was not so straightforward.

All the magma did not reach the Earth’s surface on the first eruption, or even the second. There are often multiple eruptions that occur before the magma becomes lava and an island is formed. 

The magma created underwater volcanoes, and as those continued to erupt, the lava edged closer to the ocean’s surface over time.

After dozens of eruptions, the magma finally reached the Earth’s surface and formed the islands.

This process took a long time, sometimes with a million years or more in between islands cropping up, though eruptions were happening below the sea in the meantime.

The Hawaiian Islands Formed Over Time

All of the Hawaiian Islands were not created at the same time. As you move from east to west across the hundreds of Hawaiian Islands, the islands get older.

hawaiian islands rock petroglyphs before it formed

This direction-age connection is due to the Pacific plate moving in a northwest direction. The further away an island is from the tectonic plate from which its first volcano originated, the older it is.

Most of the original islands have already eroded and have inactive volcanoes. Some of the older major islands are in the beginning stages of erosion. 

The older the island is, the more likely it is that the island’s volcano has become inactive. Newer islands tend to have more active volcanoes because of their more recent formation.

The Big Island is the youngest of the Hawaiian islands, which would explain why it has the highest number of active volcanoes.

To put the age differences between some of the islands into perspective, Oahu is significantly older than Hawaii’s island.

The two of Oahu’s volcanoes haven’t erupted or shown any activity in over one million years. In contrast, two volcanoes on the island of Hawaii erupted only a few months ago.

Is There a Possibility of New Hawaiian Islands?

When you consider how the Hawaiian Islands were formed in the first place, new islands could likely join this archipelago at some point. 

formed hawaiian islands possibility of continuously moving plates

However, this will be in the distant future if this happens. The Earth’s tectonic plates are continuously moving, which, as we know, is what caused the Hawaiian islands to form initially.

As long as geological processes stay the same, a new island is likely. Roughly 20 miles southeast of Hawaii’s island is an active volcanic site on the seafloor.

This volcanic site is known as Loihi and is predicted to be the next Hawaiian island site. As the Pacific plate continues to move, it will cross into this area, and a new island will form.

The possibility of a new Hawaiian island developing is high, but it is not something we will see in our lifetime. Scientists estimate it will take a minimum of 10,000 years. 

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