Human activity linked to nine out of ten major landslides, says Swedish expert

A landslide on Friday in Gothenburg’s Hisingen district swallowed a hectare of land, half a barn, and a horse, with a geologist warning that human influence plays a role in nearly all such incidents, Swedish public broadcaster SVT reports.

The landslide in Rödbo, northern Hisingen, dragged down part of a barn, a tractor, two cars, and a horse along a 150-metre stretch, with depths reaching six metres in places. The affected area consists largely of quick clay, a material known for its instability.

Christian Öhrling, a senior state geologist at the Geological Survey of Sweden (SGU), told SVT that human activity is a factor in roughly nine out of ten major landslides. “If you know you’re on clay, in or near a steep slope, you should be cautious with heavy groundwork and loading,” he said.

Western Sweden is particularly vulnerable due to its deep, clay-filled valleys and exposed bedrock, which allow water to easily penetrate clay deposits. While no data confirms an increase in landslide frequency, Öhrling noted that Norway experiences about one major landslide annually, whereas Sweden sees similarly destructive events roughly once a decade.

Preventive measures, such as thorough ground surveys and stabilisation, are standard in large construction projects on unstable terrain. The SGU offers public access to maps indicating areas requiring further investigation, though Öhrling stressed that darker-shaded zones do not automatically denote high-risk areas—only the need for assessment.

Property owners concerned about landslide risks can consult local authorities or the SGU for guidance.