Last week, a devastating landslide struck several remote villages in the mountainous Enga province in Papua New Guinea. The death toll is estimated to be between 690 and 2,000 people, with thousands more missing. The search and rescue operations have been challenging due to secondary slides and rock falls in the search zone, a lack of access to heavy digging machinery, and the need to clear or repair roads for assistance and equipment to arrive.
Landslides occur when the pull from gravity exceeds the strength of the geomaterial forming the slope of a hill or mountain. Slopes can fail due to earthquakes, rainfall, or a combination of both. In Papua New Guinea, the country’s location on an active fault and heavy rainfall make it prone to landslides. Human activities such as deforestation and mining can also contribute to slope instability.
Predicting landslides is extremely difficult and mitigating the risk is challenging. The recent landslide in Enga province and the numerous landslides that occur worldwide each year highlight this difficulty. Even in Australia, where the terrain is relatively flat, landslide risk is difficult to estimate and is typically not covered by home insurance policies.
To accurately assess slope stability, a three-dimensional mapping of the geomaterials and their strengths is needed. However, obtaining this information is challenging as sensors cannot provide it. Geologists and geotechnical engineers must rely on partial information obtained at selected locations and extrapolate it to the rest of the slope, which introduces uncertainty. Additionally, predicting the exact size and timing of a landslide is as difficult as predicting weather and seismic activity.
Unfortunately, accurate landslide predictions cannot be bought with money, especially in remote areas of the world.
