How Was Haleakala Formed – The Formation of Haleakala Crater, Maui, Hawaii

Haleakala Dominates the Island of Maui, not only does the huge volcano make up 75% of the island’s landmass, it towers above everything and reached up into the atmosphere pushing the moist ocean air upwards to cool it down to create the rains that keep Maui so lush and verdant. Without Haleakala, there would be no Maui and her presence dictates daily life for the island residents, tourists wildlife, and plants.

As such we think it’s right and proper to give some thought as to How Was Haleakala Formed, what forces crafted its unique structure, and what the future holds for this monster mountain and for all who live on her slopes. We also take a look at the origin of Haleakala Crater as its formation is not as most guidebooks suggest and not immediately obvious as you peer down into it at sunrise!

How Was Haleakala Formed

Formation of the Mountain

The Formation of the Mountain is a simple story and one that is told time and again on the Hawaiian Mountain Chain. The Island of Maui sits above a Hotspot in the Earth’s Mantle. The Hotspot is in the Earth’s Mantle and cuts through the Crust to Form Volcanoes, but as the Mantle is stationary but the crust moves northwards slowly over Eons via continental drift, these Volcanoes end up moving away from the Hotspot and losing their volcanic powers.

Haleakala is right at the edge of the hotspot and is moving from active to dormant. The majority of its eruptive phase is over and the mountain has begun sinking back into the ocean. Unlike its neighbors Mauna Loa, and Kilauea over on the Big Island and the still submerged Lōihi that is just getting started.

Shield Volcano
Shield Volcano by Niamh O’C on CC3.0

Haleakala is a Sheild Volcano. These are formed less dramatically than over types of volcanic structures (though still pretty dramatic!). The Lava is known as effusive. Meaning it comes out slowly. Some volcanoes can form in a matter of years as Magma pours out of the fissures. Hawaiian Sheild Volcanoes take Millenia to form as the Lava slowly seeps out, building up relentlessly, layer after layer. Haleakala has been doing this for around a million years!

It is this slow layering of Lava flows that have built all the Hawaiian islands and continues to form new lands on the Big islands and will even raise new Islands in the coming millennia,

Don’t get excited though, Lohoi is not expected to break the surface for another 10,000-100,000 years

Formation of the Crater

From above the rim of the Haleakala Crater, it has the appearance of the classic Volcanic Crater. A large deep bowl filled with vents and volcanic rock. However, the Crater itself is not of volcanic origin. It is obviously a product of volcanic activity, but it was not formed by direct volcanic actions. Quite the opposite.

Haleakala Aerial

From above you can clearly see how the crater formed. The two large valleys of Koolau and Kipahulu/Kaupo split the mountain in two. These massive valleys are a product of erosion. You can see clearly they are very reminiscent of the Iao Valley and the other deep erosional valleys of the West Maui Mountain. The difference being those valleys have deep floors filled with rivers and Halakalas are raised up giving a large flat valley floor.

This is because after Hundreds of thousands of years Haleakakla went dormant. The erosion began and the two colossal valleys formed. Eventually, they met up carving the mountain in two and removing a few hundred feet from its original height.

However, Haleakala was not done. The summit roared back into life and lava began flowing again. Numerous vents opened up filling the valley back up. Flows ran all the way to the ocean, and many vents can be seen all around the mountain. Cinder cones, lava flows, volcanic vents, and craters are shattered around the crater and at various points on the mountain slopes. All telltale signs of its recent eruptive past.

The latest flows were not enough to completely fill the crater with much of the lava channeled down the valleys. This has kept the classic crater appearance but made the depths of the valleys far less severe and gives the appearance of a volcanic crater rather than a result of thousands of years of erosion.

Haleakala currently shows no signs of a volcanic eruption which leads man to ask:

Is Haleakala Still Active?

Haleakala Towering over the clouds
The Volcano rising above even the clouds

Absolutely. By almost all measures of how scientists interpret “an Active Volcano,” Haleakala fits the bill. Its latest eruptions are only a few hundred years ago and the mountain is almost certainly not done. Even if it does move into a dormant phase it still has the chance to rumble back into life again.

West Maui Mountain is Dormant. Its life as an island-building force is spent. But it is not extinct. It may move to the final phase without ever erupting again, but most scientists believe it will return for one last hoorah before finally going to sleep forever. But Haleakala is nowhere near that phase. While she does not stir at the minute there is little doubt the Mountain will erupt again, probably several times over the next few hundred thousand years, before the continental drift moves Maui off the hot sport and finally puts the giant to rest.

Of course, that does not mean you should be overly worried. The Volcano may not erupt for another 1000 years. There are no signs at the minute of anything like an eruption event occurring. There is very little gas emanating, there are no earthquakes, and no deformation at the summit or flanks of the mountain. These are all precursors to an eruption. For now, the Mountain sleeps, but that does not mean she is inactive.

We should also mention that while remaining active, her creation days are behind her. The mountain is in the erosion phase and the abundant rains that fall on her slopes every day are beginning the process of the mountain returning to the sea.

The Hawaiian island volcanoes are so fascinating as the future of all the islands is painted across the past of the others. The youngest volcanoes sit in the south and as you move north the islands get older as the continental shelf drifts north moving over the hotspot of creation. From the still-birthing Loihi to the bristling and active Kilauea and the giants of Mauna loa and Mauna Kea which showcase the pomp and prime of the Volcanoes in full adulthood.

Haleakala Weather
The Giant mountain even dictates the Maui Weather

Haleakala is just starting to recede, while West Maui shows the scars and aging lines of a mountain past its prime (and all the more beautiful for it) Oahu, shows the effects of millennia of being worn away, while still showing the signs of a final flourish of activity in the form of its finale cinder cones, Diamond head, Koko crater, and the punchbowl crater. To the north of Oahu, almost all trace of volcanic past has gone and only the heavily eroded remnants of the mountains remain.

Kauai shows the results of millions of years of erosion. The landscapes are smoother and the peak shorter as the winds, rain, and ocean have nibbled away.

Heading further north along the emperor seamount chain the islands are now just remnants, coral atolls just peeking above the waves and further north still the volcanoes have lost their pace above the waves and only remain as underwater seamounts, lost to all and only visible via satellite.

The Fate of Haleakala is written in these islands.

Haleakala Myths and Legends!

Maui Lassoed the SUN

Maui is known as the House of the Sun. Despite the peak being considerably lower than both Mauna Kei and Mauna Loa the mountain captures sunrises far more dramatically and as such has become synonymous with the sun in Hawaiian folklore.

The Crater was the home to the Demi-God Maui’s Grandmother. And it was here he lassoed the Sun, in order to stretch the days giving more light during the summer months.

You’re Welcome.

Exploring Haleakala National Park and seeing the Sunrise!

Haleakala Crater Floor

Sunrise at the summit of Haleakala is a right of passage for Maui tourists and is right at the top of most people’s bucket lists. We love it high up o the mountain as the sun peeks over the horizon to start another day. High above the clouds, the colors are incredibly vivid and the air takes on an ethereal feel. It is truly stunning, and can be combined with a spot of stargazing beforehand where the whole galaxy pens up and you can actually see the milky way by eye!

We highly recommend it, and by using jetlag to your advantage, the ridiculously early start is not too bad.

We have a full article about planning your trip up Haleakala to visit the House of the Sun.

Sunrise on Haleakala

Have Your say

Let us know your thoughts on the formation of Haleakala? Have you visited the mountain, did you take in a sunrise? Let s know in the comments. If you have any questions about the mountain creation or want anything clarifying just fire away in the comments, we would love to hear from you.

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