Mt Kelud, Indonesia 1919
Mt. Kelud is located on the island of Java and is considered yet another of Indonesia’s active volcanoes. Over the past 600 years the volcano has erupted over 30 times and killed more than 15,000 people. It’s deadliest eruption in recent history occurred in 1919. Prior to the 1919 the danger of mud flows following an eruption of Mt. Kelud was known. The Dutch colonizers of Java built a dyke which they hoped would direct any lahars away from the city of Blitar. While the dyke was a good idea it underestimated the substantial size of the lahars the 1919 eruption would generate.
Mt. Kelud has a massive crater lake which was the cause of the destruction in 1919. When the volcano erupted 38 million cubic meters of water was pushed upward. The water then flowed through deep drainage channels picking up loose sediment and volcanic material to create lahars. These fast-moving lahar flows covered 30 square kilometers of the country side. The dykes built by the Dutch were completely overwhelmed and the lahars just flowed right over them. More than 100 villages were pushed away by the flowing mud which left nothing but destruction in its wake. 5,100 people were killed making it the deadliest modern eruption in Indonesia.
The Dutch response to the eruption was nothing short of remarkable. They learned that the dykes were not effective and therefore created a drainage system for the crater. This kept the water level from getting too high and thereby limited the water that would be shot out in the event of another eruption. They also formed the Indonesian Volcanological Authority which still operates today. The drainage system proved its effectiveness when a 1951 eruption produced no lahars.