How Much Of Hawaii Is Covered In Lava?

Hawaii, with its picturesque beaches, tropical rainforests and towering volcanoes, appears lush and green at first glance. However, the Hawaiian Islands are also home to large areas covered by ancient and more recent lava flows.

If you’ve wondered exactly what percentage of Hawaii’s total land area is comprised of lava flows, read on for a comprehensive breakdown.

If you’re short on time, here’s a quick answer to your question: Around 32-35% of the total land area in Hawaii is covered by lava flows.

In this in-depth article, we will explore the volcanic origin of the Hawaiian islands, take a closer look at the major lava flow zones, examine lava coverage percentages for each of the main islands, and summarize how much lava in total covers Hawaii.

The Volcanic History Behind Hawaii’s Lava Flows

Formation of the Hawaiian Island Chain

The Hawaiian Islands were formed by a geological hotspot under the Pacific Plate. As the plate moves northwestward over the hotspot at about 32 miles per million years, volcanoes erupt on the sea floor, eventually rising above sea level to form islands.

The islands farther northwest are older as they have moved away from the hotspot earlier. This is how the Hawaiian island chain formed over 70 million years.

Types of Hawaiian Volcanoes and Their Activity

There are two main types of volcanoes in Hawaii – shield volcanoes and cinder cone volcanoes. Shield volcanoes like Mauna Loa are enormous in size, with long shallow slopes produced by runny lava flows. They erupt less violently than cinder cone volcanoes.

Cinder cone volcanoes are smaller but erupt more explosively, building steep conical hills by accumulation of volcanic fragments.

Kilauea volcano on Hawaii Island is one of the world’s most active volcanoes. Its Puʻu ʻŌʻō vent has continuously erupted lava since 1983, adding 500 acres of new land to Hawaii Island!

Characteristics of Lava Flows in Hawaii

Molten lava can reach temperatures between 1,165 to 1,220 degrees Fahrenheit (2,000 – 2,100 degrees Fahrenheit). Hawaii’s lava flows are basaltic lava, generally thinner and runnier than other lava types. Their speed ranges from 1 mph to 35 mph, although they rarely exceed 10 mph.

Despite the appearance of gentle flows, the lava’s high temperature enables it to melt road signs and ignite vegetation, demolishing everything in its path!

USGS (U.S. Geological Survey) tracked recent lava flows from Kilauea covering over 35 square miles, equivalent to over 22,000 football fields in land area! This added tremendously to Hawaii Island’s land mass over time.

Lava Zones and Coverage on Big Island

Puna District: Lower East Rift Zone

The Puna district, located on the lower East Rift Zone of the Kilauea volcano, has seen extensive lava flows over the past decades. According to the U.S. Geological Survey (USGS), around 35 square miles of land has been covered by lava flows here since 1983, destroying over 200 homes in the process.

The most impacted area is the Kalapana region, where the active lava flows from Kilauea’s East Rift Zone enter the ocean. This has added nearly 2 square miles of new land to Hawaii’s coastline. However, it has also buried the historic village of Kalapana under 50-80 feet of lava.

Efforts by volcano experts to divert the flows have proven challenging over the years.

Kau District: Southwest Rift Zone

The Kau district lies on the Southwest Rift Zone of Kilauea, extending from the caldera down to the island’s southern shore. Compared to Puna, the lava coverage here has been relatively minimal in recent decades.

Only around 4 square miles has been resurfaced, mostly limited to the slopes of the rift zone.

However, the region has the potential for larger eruptions, like the massive lava flow in 1823 that originally formed the cinder cone of Puʻu ʻŌʻō. The recurrence of lava outbreaks in this zone prompts locals and authorities to continually monitor seismic activities for early warning signs.

Hualalai Volcano and North West Rift Zone

On the northwest region of Big Island, the Hualalai volcano makes up a third rift zone with its own complex of vents and fissures. Hualalai last erupted in 1801, sending flows downward the rift zone all the way to the ocean.

Given the long repose, the North West Rift Zone is considered the most dangerous area today in terms of lava hazard. USGS HVO scientists estimate a 60% chance of renewed activity in this zone over the next 30 years.

Contingency plans are in place for a mass evacuation if lava outbreaks begin uprift of Kailua-Kona town.

Lava Extent on Maui, Oahu, Molokai and Lanai

West Maui Volcano

The West Maui Volcano makes up a large portion of west and central Maui. This shield volcano erupted intermittently from 1.3 million to 500,000 years ago, spewing fluid basalt lava that spread over the landscape to form gently sloping flanks.

Today, about 48% of Maui is covered by lava flows from this long-lived volcano.

Haleakala Volcano

Haleakala Volcano, which forms east Maui, is another shield volcano that erupted between 1.1 million years ago to the 15th century. Over 90% of the surface on this half of Maui is covered by flows from Haleakala—over 500 square miles across east Maui is capped by lava.

Honolulu Volcanic Series (Oahu)

The island of Oahu consists of two parallel, extinct shield volcanoes called Waianae on the west and Koolau on the east. Between 1.8 and 3 million years ago these volcanoes erupted, covering much of Oahu in lava flows.

Today, lava covers over 85% of the Waianae Range and 95% of the Koolau Volcano—so over 90% of the island of Oahu is mantled by lava.

West Molokai Volcano

West Molokai volcano erupted between 1.9 million years ago to 1.5 million years ago, slowly oozing basalt lava across west Molokai. Estimates indicate about 38% of Molokai’s land area is covered by lava from this volcano, forming gently dipping volcanic plains.

Lanai

The island of Lanai emerged due to eruptions from two shield volcanoes between 1.3 million and 1 million years ago. Today over 98% of Lanai’s 141 square miles are covered in layers of lava—only a small area in the center of the island known as Garden of the Gods escaped burial by lava.

Total Lava Coverage in Hawaii: By the Numbers

The Hawaiian Islands are located over a geological hotspot in the Pacific Ocean, which has resulted in significant volcanic activity over millennia. This has led to lava flows covering large portions of the islands. Here is a breakdown of the total lava coverage in Hawaii:

Island of Hawaii

The Island of Hawaii, also known as the Big Island, has experienced the most volcanic activity of all the islands. According to estimates, around 32% or 2,034 square miles of the Big Island’s total area of 4,028 square miles is covered by lava flows.

The large shield volcanoes Mauna Loa and Kilauea are responsible for most of these lava flows.

Maui

The island of Maui has less lava coverage compared to the Big Island. Around 23% or 333 square miles of Maui’s total area of 1,448 square miles is covered in lava. The volcano Haleakala is responsible for a large portion of Maui’s lava flows.

Oahu

Oahu has relatively small lava coverage compared to the other islands. Only around 4.5% or 28 square miles of Oahu’s total land area of 597 square miles is covered by lava. The volcanoes on Oahu are considered extinct, so there has been little lava activity in recent geological history.

Kauai

The island of Kauai has experienced the least volcanic activity in Hawaii. Less than 1% or about 5 square miles of Kauai’s total land area of 552 square miles is covered in lava. The volcanoes on Kauai have been dormant for over 1 million years.

Total Lava Coverage

Adding up the lava coverage for the main Hawaiian islands results in the following totals:

• Island of Hawaii: 2,034 square miles
• Maui: 333 square miles
• Oahu: 28 square miles
• Kauai: 5 square miles

The total lava coverage in Hawaii is approximately 2,400 square miles, mostly concentrated on the geologically active Big Island. While lava has covered large portions of Hawaii, there are still areas that showcase the islands’ lush greenery and idyllic beaches.

Conclusion

As we’ve explored, around 32-35% of Hawaii’s total land area is covered in lava flows from effusive eruptions of shield volcanoes over hundreds of thousands of years. This amounts to just over 5,500 square kilometers of lava coverage across the islands.

The island of Hawaii has the greatest lava coverage since its volcanoes are the most active. Over half the Big Island is mantled in lava, especially on the slopes of massive shields like Mauna Loa and Kilauea in the Puna and Kau districts.

Older islands like Oahu and Molokai have less lava coverage, between 5-15%.

Underlying its idyllic beaches and jungles, lava layers form the foundation of the Hawaii we know today. The continuing volcanic processes ensure the emergence of more land area in the future.

Sharing is caring!