Topan Ramadhan is a Geological Engineering Student at the Faculty of Mineral Technology, Institute of Science & Technology AKPRIND Yogyakarta, Indonesia. He is the Chairman of Indonesian Association of Geologists Student Chapter at the Institute of Science & Technology AKPRIND. He actively researches on geological science topics such as geology on oil and gas, sedimentology, geological environment and disaster mitigation and volcanology. He has previously done many researches on stratigraphy analysis for oil and gas implication, geological structure for a petroleum implication.


The volcano eruption is one of the events that frequently occurs in Indonesia, particularly in Java Island with the island arc, while the material is in the form of glowing clouds of hot, lava flow, lahar and avalanches of volcanic and much more. Merapi is a most active volcano in the world. This research focuses on the deposition of lahar, which is located in the district of Sleman, Magelang Regency and surrounding areas, with the object of research Krasak river, the Putih river and the Blongkeng river tipped in Mount Merapi as an analogy at the Southwestern part modern sedimentology especially on the river at the foot of volcanoes. The study covers analysis of field observations such as lithology, stratigraphy and direction measurement, lahar deposition, as well as more detailed observations in the laboratory by analyzing the grain structure by morphometric methods and the correlation of stratigraphic and abundance of lahar sediment at the foot of Mount Merapi. Three units of obtained Lahar (SSL) include, the SSL 1: More lava is deposited on the river Krasak Blongkeng with a thickness of 4 to 7.5 meters; the lahar flows more in the ancient current directions N214oE Blongkeng River and River Krasak N 187oE; SSL 2: Many on Krasak River and SSL 3: The Putih River has a thickness of 4-10 meters, as well as current directions are: N190oE Krasak River and the Putih River N 205oE. The data show the displacement of sediment input variations of lahar from Southwest to the South. Data shows the influenced displacement of the craters morphology as a supporting factor for the lahar flow channels. This study explains material volume and Merapi volcano eruption deposition process and expected as a mitigation disaster and finds out lahar flow deposition area for the next volcanic eruption.