Hot Discovery! Mystery of Volcanic Avalanche Explained for the First Time

The workings of the internal structure of volcanoes have finally been observed for the first time. Using a unique eruption simulator, researchers at the Massey University looked at how the deadly volcanic flows, also known as pyroclastic flows, form.

Smithsonian Institution's National Museum of Natural History defines pyroclastic flows as "mixtures of hot gas and rock that travel gravitationally down the flanks of a volcano at highway velocities." The searing hot temperature of the pyroclastic flow and its ability to travel fast from high elevation makes it one of the most dangerous natural phenomena. This natural volcanic occurence is often called "volcanic avalanche" because they are fast-moving.

"Pyroclastic flows are the most common and lethal volcanic threat, and by analysing the internal structure we are laying the foundations to understand how they will behave in an eruption," says Dr. Gert Lube from Massey's Institute of Agriculture and Environment, one of the author's of the paper published in Nature Geoscience.

According to the press release published on the university's website, studying the workings of the hot gas and rock in an actual volcano is impossible because of the high temperature and danger associated with it, so they decided to make a replica of a volcano which will allow them to measure the inside of an avalanche, including its hot gases and rocks.

By simply dropping ash and pumice down a narrow channel, they were able to recreate the natural behavior of the flows. To capture the data and movement, they used high-speed cameras and sensors.

As noted by the Science Explorer, the experiment was able to identify a previously unrecognized "middle zone," where the two known currents (a non-turbulent underflow and a turbulent hot ash plume) meet.

"Inside this middle zone, the gas-particle mixture behaved fundamentally different from the turbulent suspension cloud above and the particle-rich avalanche of pumice below. Instead, the volcanic particle spontaneously associated in a pattern of dendritic particle clusters called mesoscale clusters," Lube said.

He further explains that these identified mesoscale clusters determine the "damage level" that pyroclastic flows will make during a volcanic event.

The discovery will pave more efficient ways to make accurate volcanic hazard forecasts, which, in turn, will save the lives of many people exposed to volcanic danger.

"This research replaces the existing theories and long-standing paradigms that have underpinned how we understand and ultimately protect people against the flows," he concluded.

Pyroclastic flows, according to the University of Massachusetts, have caused about 55,000 deaths since 1600 A.D. Most of them died of asphyxiation from the dust, burning and dehydration because of high temperature and the impact of ash and debris driven at high speeds.