Variable Eruption Patterns of Hawaii's Mt. Kilauea Explained

Hawaii's iconic Mt. Kilauea volcano has variable eruption patterns that scientists have attempted to explain after synthesizing centuries worth of volcano data from the islands.

Kilauea, located on Hawaii's Big Island, is the state's youngest and most active shield volcano. The volcano is erupting nearly constantly, with the current eruption phase having gone on since 1983.

Kilauea's dominant form of eruption is effusive, where magma flows create ropey lava known in Hawaii as pāhoehoe lava.

But occasionally Kilauea erupts more violently, raining volcanic matter down on the island.

New research by the University of Hawaii's School of Ocean and Earth Science and Technology, the Hawaiian Volcano Observatory and University of Cambridge explains the variable eruptions of Kilauea, revealing that whether an eruption will be explosive or effusive has to do with what's happening with magma deep below the surface.

Variability in the composition of deep magma is what leads to explosive or effusive eruptions, with the more gas-rich magmas producing the more explosive eruptions.

"Gas-rich magmas are 'predisposed' to rise quickly through the Earth's mantle and crust and erupt powerfully," said University of Hawaii volcanologist Bruce Houghton.

For scientists mapping real-time hazards and risks associated with volcanic eruptions, being able to predict the type or eruption and the direction it will flow in are critical. At an early stage, it is difficult to make accurate predictions of which way the eruption will flow and what form the eruption will take on.

"Other statistics like a volcano's volume, eruption rate, and duration are keys to real-time hazard and risk mapping," said Houghton. "They are the target of approaches like ours."

Through analyzing the physical and chemical properties of eruptions on Kilauea with data collected from 25 eruptions within the last 600 years, the team was able to get a better understanding of the underlying causes of the variability in eruption types on Kilauea.

"Pre-existing wisdom had it that the form of an eruption was principally decided during the last kilometer of rise towards the surface. But now we know the content of dissolved gas at the deep source is a key," Houghton said in a statement.

Future Kilauea studies will attempt to offer more accurate models for predicting how fast magma rises through the volcano prior to eruption.

Houghton and his collaborators published their work in the journal Nature Geoscience.