As urban centers in mountainous regions grow, more people are driven to build on steeper slopes prone to slow-moving landslides, a new study finds. Slow-moving landslides are frequently excluded from estimates of landslide risk, but they could threaten hundreds of thousands of people globally, the researchers conclude.
As urban centers in mountainous regions grow, more people are driven to build on steeper slopes prone to slow-moving landslides, a new study finds. Slow-moving landslides are frequently excluded from estimates of landslide risk, but they could threaten hundreds of thousands of people globally, the researchers conclude.
Slow-moving landslides can move as little as one millimeter per year and up to three meters per year. Slopes with slow-moving landslides may seem safe to settle on; the slide itself may be inconspicuous or undetected altogether.
As the slide creeps along, houses and other infrastructure can be damaged. The slow slide can accelerate abruptly, likely in response to changes in precipitation. Sudden acceleration can worsen damage and, in rare cases, lead to fatalities.
Those same slopes may be repopulated years later due to pressure from urban growth, especially when floods drive people from lower-elevation areas. Nearly 1.3 billion people live in mountainous regions, according to the IPCC, and that number is growing.
« As people migrate uphill and establish settlements on unstable slopes, a rapidly rising population is facing an unknown degree of exposure to slow landslides—having the ground move underneath their houses », said Joaquin Vicente Ferrer, a natural hazards researcher at the University of Potsdam and lead author of the study.
