Dynamics of Lahar Material Deposition Post 2014 Kelud Eruption of Bladak River

Abstract

Kelud volcano eruption on February 2014 has a tremendous impact on several around volcanic prone areas. Bladak catchment on the west flank of Kelud Volcano is the most affected area post-eruption in 2014. This area covered by pyroclastic material and lahar. Lahar is the most potential hazard in the study area. Lahar hazard in Bladak river has long records not only from the current eruption but also from several past eruptions. The dynamics of lahar material deposition necessary needed to study in order to understand the physical characteristics of lahar. Field survey and GIS was used to gain information about lahar deposition characteristics. The results showed there were two different factors on lahar depositions behavior: 1) natural geomorphologic process and, 2) human-induced on river environment. The natural process shows that lahar on Bladak has different materials from the lithofacies analysis. Human activities on the river have a positive impact on normalizing the flow of the Bladak river to reduce the danger of lahar floods.