Complex system analysis show anti-crack fractures cause slab avalanches
Researchers led by a team at the University of Edinburgh, have discovered the way avalaches are caused are are from anti-crack fractures under the surface that cause the underlying layer of snow to crumble inwardly. The crumbling inner layers cause the upper layers to slide off, creating an avalanche. Made within the framework of the TRIGS ('Triggering of instabilities in materials and geosystems') project, and usingcomplex systems analysis tools to explore the triggering mechanisms of natural catastrophes such as avalanches, earthquakes and landslides, it will, as an anti-crack itself, lead to an avalanche of further research.
Up until now, geologists believed that slab avalanches were caused by shear cracks. This is when one layer of snow slides off another. These avalanches are often triggered by skiers and are the cause of countless skiing accidents.
"Our discoveries complete a piece of the puzzle of how avalanches occur. We hope this will help to pinpoint dangerous
tell-tale signs and so avoid unnecessary dangers to people on mountains," said Joachim Heierli (right) Research Associate at the Centre for Materials Science and Engineering at the University of Edinburgh. Dr Heierli and his colleagues published their findings in the latest edition Science.
Their research has some serious implications for skiers and where they can ski. As a result of computer modelling undertaken by the research team, skiers moving over flat ground or across small slopes can no longer consider themselves entirely safe. This is because long-distance fracture propagation may trigger avalanches on overlying slopes.
The TRIGS project is funded under the NEST ('New and emerging science and technologies') part of the Sixth Framework Programme (FP6). The EU provided over €1.6m in funding for this project out of the €2.1m total cost of the project. The members of this consortium come from diverse backgrounds such as complex systems, materials and earth sciences, and are all internationally recognised.
Source: http://www.sciencemag.org/
Web: http://www.see.ed.ac.uk/~jheierli/