Day_199 : Early Signs of Geological Changes Before Landslides

Before significant landslides occur, various clear natural changes are often observed. Notable incidents include the 1963 Vajont Dam landslide in Italy and the 2006 Leyte Island landslide in the Philippines.

On the evening of October 9, 1963, a massive landslide took place near the Vajont Dam in the Alps of northern Italy. The dam, standing at 262 meters, was completed just three years prior. The landslide dislodged approximately 260 million cubic meters of earth, thrusting up the waters of the dam’s lake. The displaced water surged over the dam, rising more than 100 meters before rushing down into the valley below, resulting in approximately 2,000 fatalities. The geological layers in the area were unstable, compounded by the increased water levels from the dam. A minor landslide had previously occurred in 1960, and the landslide’s progress accelerated to several tens of centimeters per day just before the disaster. Despite ongoing monitoring, the catastrophic damage could not be prevented.

Day_140 : Natural Disasters in Europe (2) Vajont Dam Collapse


On February 17, 2006, a mountain 800 meters tall on the Philippine island of Leyte succumbed to a vast landslide, displacing around 20 million cubic meters of soil and claiming 1,144 lives. Before the collapse, cracks had appeared on the mountain’s ridge, and rainfall had begun to seep into the ground.

Identifying these early signs of geological change is crucial. By monitoring their progression and predicting potential danger zones, we can enhance our preparedness and safeguard our lives against such devastating natural disasters.

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