When rocks and boulders come loose from steep slopes, people and buildings in the valley below are placed in great danger. We research rockfalls so that risks can be assessed and damage prevented. Through our research, we not only get stones rolling - we move mountains.

In a mountainous country like Switzerland, not everything that comes from above is good: 6 to 8% of Switzerland's surface area is unstable ground – mainly in the pre-alpine and alpine regions. In 2012 alone, rockfalls and rock slope failures claimed the lives of five people in Switzerland. The threat of rockfall can increase as a result of climate change: melting glaciers and thawing permafrost release rocks and boulders from their icy grip.

Rolling stones

If you want to be able to calculate natural hazard processes, you first of all have to understand them. Experiments which use real rocks mounted with sensors provide the basis for this. This data is then fed into the rockfall module of our computer programme for simulating natural hazard processes: RAMMS::ROCKFALL.


RAMMS::ROCKFALL is the third module in the RAMMS simulation software. The model uses newly devised rules to calculate every contact that the boulder makes with the ground. It simulates complex motion sequences like rolling, sliding and jumping, or sudden changes of direction. This makes it possible to determine how high and far the rocks will jump, at what speed they will hurtle down towards the valley below, how the terrain will affect their trajectory and where they will land, be stopped or naturally come to rest.

What's more, for the first time the new model makes it possible to use real, three-dimensional rock shapes and calculate their trajectories. This is a major step forward, since until now many programmes were merely capable of simulating simple spherical forms.

What is especially important for practical applications is the ability to perform statistical analyses, which are essential for planning protective measures such as calculating the appropriate dimensions for rockfall protection nets.

Research group

RAMMS Rapid Mass Movements

We develop RAMMS, a software package that allows to evaluate natural hazard processes and to facilitate an assessment of the influences of protective measures

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