Debris flows and flash floods in the Putih River after the 2010 eruption of Mt. Merapi, Indonesia

摘要

After the 2010 eruption of Mt. Merapi in Indonesia, many instances of debris flows and flash floods occurred in the Putih River basin. The characteristics of debris flows and flash floods were analyzed using images of these events captured by an internet protocol (IP) camera installed near the PU-C11 sabo dam and rainfall records collected at the Gunung Maron observation station. The magnitude of debris flows and flash floods during the 2011–2012 rainy season was smaller than during the 2010–2011 rainy season. Additionally, the rainfall intensity that caused no debris flows or flash floods during the 2011–2012 rainy season was smaller than that observed during the early 1990s, when few debris flows and flash floods occurred. These results suggest that the hydrological regime of the catchment area was radically altered after the eruption.