Landslides often leave severe consequences. The question arises: why do landslides occur, and why can we not prevent this phenomenon?
What Causes Landslides?
According to the Centers for Disease Control and Prevention (CDC), landslides are caused by the natural disturbance of a slope. The most common natural causes include heavy rainfall, droughts, earthquakes, or volcanic eruptions.
An illustration showing a landslide event. (Photo: CNA).
Importantly, landslides can also be indirectly influenced by human activities, such as land-use changes and the destruction of vegetation on slopes.
At this point, any abnormal weather event (often due to heavy rain) can trigger a landslide, posing dangers to road users, local residents, and disrupting traffic.
Many landslides caused by human activities can be avoided or mitigated. They are often the result of building roads, structures, or agricultural practices without proper management on slopes, leading to poorly coordinated and scientific drainage systems.
The loss of natural forests is also one of the causes leading to landslides. In many areas, forest coverage can be as high as 70-80%, but if these are only secondary or planted forests, they are not very effective in preventing landslides, as their root systems do not develop sufficiently to retain water.
According to the World Health Organization (WHO), landslides can spread more widely than any other geological event and can happen anywhere in the world. It is estimated that from 1998 to 2017, landslides affected about 4.8 million people and caused more than 18,000 deaths.
WHO states that climate change and rising temperatures will especially lead to more landslides, particularly in mountainous areas with snow and ice. The reason is that when permafrost melts, rocky slopes can become more unstable, leading to landslides.
Landslides can occur due to various factors, including human actions. (Illustrative image: LinkedIn).
Why is it Difficult to Warn About Landslides?
The United States Geological Survey (USGS) indicates that landslides can be prevented through the installation of multi-hazard monitoring systems, which can monitor specific slopes.
However, the feasibility of this method has many limitations, as mentioned earlier, landslides can occur everywhere.
Therefore, this method is only effective for areas with very high and high landslide risk. Conversely, in areas with low or very low landslide risk, this approach is ineffective because it’s uncertain when a landslide may occur.
Typically, expensive monitoring systems are prioritized for installation on certain critical slopes, where a landslide could have serious consequences for people and infrastructure, such as highways near large residential centers…
In contrast, predicting landslides in natural slopes in rural and pristine mountainous areas remains a pressing issue. This is not only a challenge for Vietnam but also for advanced countries like the United States and Japan.
According to USGS, high-risk landslide terrain includes areas with steep slopes and high embankments, but little or no vegetation to hold the soil.
Additionally, geological areas that show changes in natural structure, such as urbanization, deforestation, and lack of drainage systems, are also high-risk landslide terrains.
