Lava

According to Native Hawaiian tradition, molten lava is the manifestation of Pele— the volcanic deity and creator of new lands. She is a rejuvenating and creative force, reshaping the landscape with each eruption. Indeed, molten lava that reaches the surface during volcanic eruptions is still adding mass to the island of Hawaiʻi. The island itself is made up of flows that have built upon one another over many thousands of years.

 

Whether it is solidified or molten, lava is everywhere on the island of Hawaiʻi

NPS Photo/J. Wei

 

Solidified pāhoehoe lava

Two types of lava flows can be seen in the park, pāhoehoe and ʻa‘ā.

Pāhoehoe lava appears smooth and ropy. It moves slower and stays hotter than ʻaʻā lava. When flowing, it can form lava tubes and may have many flow units known as "toes" because it is more runny and less viscous.

 

Solidified ʻa‘ā lava

ʻA‘ā lava, by contrast, appears rough, jagged, and chunky. It moves fast, with high velocity, and loses heat quickly while flowing. ʻA‘ā lava is much more viscous than pāhoehoe and flows in fewer, larger channels.

Most flows consist of both pāhoehoe and ‘a‘ā at various points, though the proportion of each can vary widely. Pāhoehoe upstream often changes to ‘a‘ā downstream. Although it is possible, ‘a‘ā flows transition into pāhoehoe less often.

 

 

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 Puʻuʻōʻō.

 

Eruptions

 

Learn about some of the previous eruptions of Kīlauea and Mauna Loa