THE BIG ISLAND

A TALE OF FIVE VOLCANOES

Pahoehoe Lava, Kalapana 1988
© 2025 by Gregory Dunaj

How big is the big island you may ask? Well, the land mass of all the other islands in the Hawaiian archipelago can comfortably fit inside the big island.

There are 5 volcanoes on the island and two of them, Mauna Loa and Kilauea, are extremely active. Mauna Kea is considered “active” although it last erupted 4,000 years ago. Hualālai is another volcano. It last erupted in the early 1800’s and volcanologists think it is just a matter of time for another eruption. Kohala is the oldest and considered extinct. It last erupted 60,000 years ago.

Despite all these volcanoes the Big Island is a very popular tourist destination but depending on what you are interested in, and if you have limited time, you must decide between the Kona coast or the Hilo side. They are vastly different. 

First, a bit more about the volcanoes which are all considered mountains.

Kilauea is the youngest volcano on the Big Island and the most active volcano in the world. Kilauea has been erupting since 1983.

Here’s a link to a 24/7 livestream of Kilauea caldera:

KILAUEA CAM

Mauna Loa is a massive shield volcano that last erupted in December 2022.

Mauna Loa from our Waikoloa resort

Mauna Kea is also a shield volcano.

If measured from its base on the ocean floor Mauna Kea would be the tallest mountain in the world. At 33,500 feet in elevation this summit surpasses Mt. Everest by approximately 4,450 feet. Mauna Kea rises 13,796 feet above sea level and near the summit there are several international observatories.

Kailua Kona with Hualalai in background

Mauna Kea is considered a spiritual place by native Hawaiians. To read about Mauna Kea:

THE IMPORTANCE OF MAUNA KEA

 

Hualālai is the western-most volcano and looms over the thriving Kona coast. Kailua Kona is the main “city” on the western side of Hawaii (the actual name of “the Big Island”) and it is where the Ironman Triathlon is held. Most of the Kona coffee plantations are found in this area of the island.

Mauna Kea observatories

Kohala is the oldest volcano on the Big Island and last erupted 60,000 years ago and is considered extinct. The mountain extends out from the island like a finger. This area is called the Kohala coast and some of the best beaches on the island are here.

Shield Volcanoes

The volcanoes on the Big Island are shield volcanoes. They are large broad mountains with gently sloping sides that look like a warrior’s shield on its side. This shape has been built up by repeated eruptions where the lava, either Pahoehoe or A’a, oozes out of the craters and rifts and solidifies atop the older lava flows slowly adding to the height of the mountain.

Pahoehoe is a smooth billowy lava while A’a is rough and jagged. I first visited the Big Island in 1988 and photographed the Pahoehoe flow that was covering the town of Kalapana at the time. That picture is featured at the beginning of this entry.

In 2018 the lower rift zone erupted and added a full square mile to the island and the Isaac Hale Beach. Here are two pictures from our recent visit to that area and you can see the difference in  A'a lava:

 

A'a lava from 2018 eruption

new land at Isaac Hale Beach

To read more about shield volcanoes:

SHIELD VOCANOES 

KONA v HILO

Now all this yammering about the volcanoes of the Big Island may not seem important, but they do impact the weather on the island. The Kona / west side is leeward and is much drier than the Hilo side. On the east side of the Big Island the prevailing trade winds from the northeast carry moist air from the ocean and encounter the two mountains of Mauna Loa and Mauna Kea and rise, cools and condenses and there is a lot of rain. When the winds descend, they become drier as they reach the leeward or Kona side. Kona is the Hawaiian word for leeward.

Many of the resorts on the island are on the Kona and Kohala coast and some of the best beaches are located here. Some of the best snorkeling spots are on the Kona coast and it is possible to go swimming at night with Manta Rays.

Kua Bay, Kohala coast

Lush rainforests and waterfalls are on the Hilo side, which is much closer to Volcanoes National Park. The beaches here are black lava sand and turtles are everywhere.

swimming with Manta Rays

We were on both coasts for this last trip, spending time at the Waikoloa Hilton resort and then a vacation rental outside of Hilo where it rained nearly every day.

Richardson Ocean Park, Hilo 

Mahalo for reading

Love Janet and greg

© 2025 by Gregory Dunaj