History and Development of Drainage Tunnels for the Crater Lake of Mt. Kelud in Indonesia

Volcanic eruption causes pyroclastic flow, lava flow, volcanic bomb and ashfall disasters simultaneously, furthermore lahar disaster due to rain in the aftermath. In rare case it causes a lahar by crater lake outburst at the moment of eruption, damaging tremendously. This rare lahar disaster is not only terrible in damage but also difficult in countermeasure. The paper investigated existing drainage channels of countermeasures for this rare lahar through research papers and evaluated the effectiveness, resulting in a fact that excepting the Mt. Kelud case they aimed to confine an imminent outburst of crater lake formed after an eruption and are not effective for the next eruption. In the Mt. Kelud drainage tunnels were constructed to confine this rare lahar in 1928, and is functioning as of now by improving through several times of eruptions. The paper reviewed the construction and improvement history of the crater lake drainage tunnels in Mt. Kelud, and evaluated the function as a countermeasure for the lahar caused by crater lake outburst.