Breakthrough X-ray System Reveals Secret Flows Behind Landslides
By David Freeman - August 29, 2025
Avalanches and landslides have long been viewed as unstoppable walls of destruction, cascading with the speed and force to level entire landscapes. Yet the true inner workings of these events have always remained obscured. Scientists could measure the aftermath, track surface motion, and model forces, but what happened beneath the rolling surface was hidden. For decades, researchers have suspected that invisible currents and loops twist inside these torrents, redistributing energy and shaping their deadly power. Until now, these forces could not be seen directly, only imagined through theory or hinted at in computer simulations. A new breakthrough has changed that picture dramatically.
An international team led by the University of Sydney has built a custom X-ray imaging system capable of watching through flowing soil, snow, and even industrial grain. With this technology, known as DynamiX, they have for the first time confirmed the existence of secondary flows inside granular material. The system works by firing multiple X-ray beams through a moving pile of particles, capturing in real time the subsurface motions that the human eye could never witness. What they discovered were loops, eddies, and swirling structures buried inside, ghost-like forces guiding the flow from within. These secondary flows had been proposed for years as a possible explanation for unpredictable collapses, but until now no one had seen them in three dimensions as they happened.
The implications reach far beyond academic interest. Avalanches on mountain slopes, landslides after storms, soil failures at construction sites, and sudden silo collapses all involve the behavior of granular material. These hidden flows may help decide whether a slope remains intact or gives way, whether a grain pile discharges smoothly or clogs catastrophically. The discovery transforms how such events are understood and how they might be prevented. For industrial sectors handling powders, grains, or minerals, the ability to see and model these flows means safer storage and more reliable processes. For engineers dealing with natural hazards, it means building models that account for the forces previously hidden below the surface.
The DynamiX system itself represents a remarkable piece of engineering. According to the research team, no equipment existed on the market capable of this task. They had to build their own from scratch, a project that took five years of construction and nearly a decade of planning. The modular frame houses multiple X-ray tubes and detectors that can be repositioned to capture three-dimensional views of a moving mass. In their first demonstration, the scientists placed a pile of glass beads on a conveyor belt to simulate granular flow. As the belt moved the beads forward, the X-ray system revealed how the surface bumps and dips were connected to invisible swirls of motion beneath.
What the images showed confirmed a long-standing suspicion in physics. While most of the particles appeared to flow smoothly forward, faint loops formed inside, twisting and rolling in ways that redistributed momentum. These hidden motions are what physicists call secondary flows. They are slow compared to the main forward rush, but they matter because they redirect how forces are transmitted through the mass. The walls of the container, for example, helped organize the flows, guiding their shapes and altering the way the entire pile moved. Without accounting for these effects, models of avalanches, landslides, or industrial discharges are incomplete.
The team processed their X-ray images with new algorithms designed to track particle motion through the dense interior. From these data, they reconstructed velocity fields showing exactly how grains moved relative to each other inside the pile. For the first time, the elusive swirls were not only detected but mapped in three dimensions as they formed and evolved in real time. Simulations had hinted at such structures, but without experimental confirmation, their role remained uncertain. This research closes that gap, establishing secondary flows as a fundamental part of granular physics.
Professor Itai Einav of the University of Sydney described the result as a long-awaited breakthrough. He noted that granular materials are everywhere in daily life, from tiny grains of sand and snow to crushed rock in minerals processing. These materials can act like solids when jammed, then suddenly flow like fluids under stress. That dual nature makes them unpredictable and dangerous. Avalanches can transform from calm snowpack to roaring walls in seconds. Silos can discharge smoothly one moment and collapse the next. Landslides can remain quiet until a hidden redistribution of force triggers disaster. The confirmation of secondary flows offers a framework for understanding these transitions.
Co-author Dr. Andres Escobar-Rincon highlighted that the original motivation was to study how granular flows behave when they strike obstacles. But when the researchers began seeing strange variations on the surface and checked them with their X-ray system, they realized they were witnessing something deeper. What they found went beyond their initial scope, pointing toward universal behavior inside moving granular masses. That realization shifts the conversation from isolated events to a broader principle of how granular material behaves under stress.
The practical applications are vast. In construction, knowing how soil redistributes force when it moves means safer foundations and better slope stabilization. In agriculture, understanding how grain moves in silos and storage facilities could reduce catastrophic failures that destroy crops and infrastructure. In planetary science, predicting how soil or regolith moves on other worlds such as Mars will be critical for building safe habitats. If slopes on Mars collapse in ways similar to those on Earth, secondary flows may be the invisible factor determining success or failure of future settlements.
DynamiX itself is not limited to glass beads. It can penetrate soil, sand, and even foams, opening the door to research across multiple industries. With the combination of real-time imaging and advanced algorithms, it acts as both a diagnostic tool and a research platform. The researchers plan to extend the system to explore how secondary flows originate and whether their strength depends on the properties of the material. Understanding that relationship could allow engineers to predict when flows will remain stable and when they will destabilize, shifting from harmless movement to catastrophic collapse.
This research, published in Nature Communications, marks the first experimental confirmation of a phenomenon that has hovered over physics for decades. By building a machine to see the unseen, scientists have exposed the ghost-like engines inside avalanches, landslides, and silos. Their discovery does not end the mystery but reframes it, giving researchers a tool to pursue answers that were unreachable before. The danger of avalanches and landslides remains, but with this knowledge, the invisible forces within them are no longer beyond our view.
Source:
Escobar-Rincon, A., Baker, J. L., Guillard, F., Faug, T., & Einav, I. (2025). Experimental confirmation of secondary flows within granular media. Nature https://doi.org/10.1038/s41467-025-62669-y ChristopherBlackwell
Seriously complicated science, but incredible discovery! Pikes will love this!
However reduction of an avalanche to a quanfifiable experiment in lab conditions meets the infinite number of variables and variations caused by the land shape alone, as no two slopes are alike. Lab and computer simulations identified many of the unseen physics within an avalanche cloud, but variations of terrain in the wild amplify, diminish and steer inertia. The truism of no two snowflakes alike exists with no two avalanches alike. Even avalanches that occur several times a year on the same slope.
Where the study is more useful is in construction of infrastructure to protect electrical and communications towers, and even private property to some degree.
In the devastating 2018-19 winter, one colossol avalanche ran for four miles in the Snowmass Creek drainage near Aspen. It wiped out everything, forest, houses... except one house whose owner build an uphill retaining wall in the shape of a ship's bow, that split the avalanche, steering it to one side or the other of his house.
Another true thing about avalanches is you must go out of your way to get in their way. Like skiing in the back country below known avalanche chutes after a storm has loaded the slope with a large cornice and slabs of hard, windpacked snow ready to split apart and slide like the felon walking on a floor covered with marbles.
You can look away from a painting, but you can't listen away from a symphony
Cool! How did you get all of that video of so many of them?
Posted by Sia on September 2, 2025, 11:50 pm, in reply to "He does" ADMIN
Did you do the videos yourself or get them online to set your music to?
on September 2, 2025, 6:41 am
