Natural disasters are very difficult to predict. No one knows when the next earthquake is going to happen or another landslide is going to demolish a mountain town. In fact, we cannot even predict the pace of a landslide. But this is changing as scientists from the University of Tübingen and the University of Helsinki developed a new technique that allows measuring the pace of landslide erosion with a handful of sand.
2015 landslides in Nepal were devastating and opened the eyes of scientists to the current limitations of our methods of studying landslides. Now scientists developed a rather simple way of measuring landslide activity. They simply take a handful of sand from a river and measure the chemistry of the sediments. Data they collect is then put into computer models that estimate landslide activities upstream from where the sample was taken. Scientists get to know a lot of factors, such as how long landslide produced sediment was in the river before being flushed out.
The method itself might be simple, but it is actually constructed from many complicated parts. Scientists have to decide where the sample of sand should be taken from, how much sand is needed, what methods can be used to analyse its constitution. The computer model itself has to be based on a lot of data, including the river flow information, sediments around the area and so on. Previous studies were limited in their inability to determine the frequency of landslide or their significance. But this new method seems to solve that problem.
Why is it important? Well, scientists will able to monitor the status of a landslide. They will be able to predict more accurately how often landslides occur. And they will also be able to determine for how long after a landslide sediments are affecting the river flow.
Scientists found that landslide sediment is actually moving rather quickly. David Whipp, lead author of the study, said: “while sediment in many river systems may be stored for tens of thousands of years, our results suggest most of the sediment in the steep Himalayan Mountains remains in the river system for no more than ten years”. Landslides in Himalaya are actually quite seasonal, because monsoons are seasonal as well. Powerful rivers remove sediment and send it downhill with immense power. This always has to be in mind when planning trips and constructing buildings.
Landslides are still going to be difficult to predict. We are talking about vast territories with varying factors. However, studies like this can improve our knowledge about the progression of a landslide and could lead to new solutions preventing huge catastrophes.
Source: University of Helsinki