Volcanoes / Lava Flows

One of Kaloko-Honokōhau's ʻa'ā lava fields. This type of lava is characterized by its sharp and jagged surface. The smoother (and friendlier to walk on) type of lava is known as pāhoehoe.

NPS Photo

Kaloko-Honokōhau has several volcanic flows within its boundary, originating from Hualālai volcano (see photo). But unlike some recent eruptions from its sister volcanoes Kīlauea and Mauna Loa, these eruptions happened long before Kaloko-Honokōhau became a park.

Flows from three different ages have been identified in the park. In years before present, they can be categorized as:

1. 10,000 to 5,000 years before present (BP)

2. 5,000 to 3,000 BP

3. 3,000 to 1,500 BP

The most recent eruption of Hualālai occurred less than 250 years ago (in 1800-1801) and deposited lava four kilometers north of the park. These volcanic features can be seen along the Queen Kaʻahumanu Highway!

 

All About LAVA.....

Lava or Magma?

Magma and lava are the same substance, but in different places. The term magma refers to molten rock that is still within the earth. Once it breaks through the earth's surface, it is referred to as lava.
 

How HOT is Hot Lava?

The temperature of erupting lava from Kīlauea is about 2,100 degrees Fahrenheit (1,150 degrees Celsius). Erupting lava cools quickly when it is exposed to air, hundreds of degrees per second, though rocks may steam for years after an eruption.
 

Why Don't Hawaiian Volcanoes Explode As Violently As Others?

Although powerful, Hawaiian volcanic eruptions are famous for being relatively benign and approachable, in comparison with volcanoes elsewhere. Hawaiian eruptions are not nearly as explosive as those like Mount St. Helens in 1980. The reason for this lies in the chemical composition of the magma that feeds these volcanoes.

Hawaiian magma contains comparatively little silica and is highly fluid. Accordingly, it can flow relatively freely and release gas easily. On the other hand, the magma of volcanoes located along the edges of tectonic plates, such as Mount St. Helens, has a different composition that makes it much more viscous (less fluid). It tends hold more gas and break apart, possibly explosively, during eruptions.

The easy flowing, fluid nature of lava from Hawaiian volcanoes contributes to their shape and is why they are referred to as shield volcanoes. Lava easily flows down the sides of the volcano, giving it a rounded appearance like a Roman warrior's shield.

 

Graphic courtesy of USGS Hawaiian Volcano Observatory

 

What Does Lava Sound Like?

An episode of the Voices of Science podcast from the National Park Service explores lava and features sounds of the 2008-2018 summit lava lake and flows from Puʻu ʻŌʻō.
 
 

 

A simplified cross-section of Hawaiʻi Island and the Hawaiian hot spot (NPS Graphic)

NPS

Volcanoes

Volcanoes are monuments to Earth's origins, evidence that its primordial forces are still at work. Over time, these prodigious land builders have created the Hawaiian island chain itself. Kīlauea and Mauna Loa are still adding to the island of Hawaiʻi and put this incredible phenomenon on full display.

 

Why Are Volcanoes Here?

The eight Hawaiian Islands we know today are only the most recent formations in a chain of over 80 volcanoes that stretch for thousands of miles to the northwest, both above and below sea-level. The further southeast in this chain, the younger the volcano, ending with the island of Hawai’i and Lō‘ihi, a growing volcano still beneath the ocean’s surface.

All of the volcanoes (both active and inactive) in this long chain formed because of the Hawaiian hot spot, a stationary plume of super-heated material deep in the earth. Heat from this material rises, eventually melting rock into magma. The magma then continues to rise. When some of it pushes its way to the surface, a volcanic eruption takes place.

The exact size of the Hawaiian hot spot is not fully understood, but it is large enough to encompass most of the Island of Hawaiʻi. Some scientists estimate the hot spot to be about 200 miles across, with much narrower vertical passageways that feed magma to the individual volcanoes.

Meanwhile, the Pacific Plate, one of the several tectonic plates that move around the surface of the earth, migrates slowly to the northwest. As it moves an estimated 2-4 inches per year, it carries with it any land that formed during volcanic eruptions.

The result is like an assembly line. The hotspot stays in one place, producing new land through eruptions, and the pacific plate carries them away. The geological formation of the Hawaiian Islands through this process mirrors the legendary journey of the Hawaiian volcano deity Pele to the island of Hawaiʻi.

Eventually, the Island of Hawai’i too will be moved by the tectonic plate away from the hotspot. It will follow in the footsteps of the older Hawaiian Islands to the northwest, and volcanic activity on the island will cease. New volcanic islands, still unborn, will come up behind it.