Identifying volcanic ash through magnetic parameters: Case studies of Mount Sinabung and other volcanoes

Abstract

Some volcanoes erupt quite frequently on roughly predicted time interval so that the populations in their vicinities are used to volcanic hazards and are prepared mentally to deal with them. However, some volcanoes like Mount Sinabung erupt infrequently so that the previous eruptions were not recorded in the collective memories of the population living in their vicinities. Studying volcanic ashes from Tengger Volcanic Complex, Santoso et al. reported that each eruptive event has unique set of magnetic parameters inferring that magnetic parameters could be used as finger prints for volcanic ash. In this study, volcanic ash samples from Mount Sinabung, Mount Soputan, and Mount Kelud were subjected to magnetic measurements as well as to X-Ray Fluorescence (XRF) analyses to establish their magnetic characteristics. The results were then also compared with that of Tengger volcanic complex. The most obvious characteristic was found to be the plot of mass-specific magnetic susceptibility and frequency-dependent magnetic susceptibility. Each volcanic sample has a distinct position in the plot. This finding implies that the eruptive history of volcanoes such as Mount Sinabung can be studied through studies of volcanic ash layers in outcrops, lake sediments as well as in marine sediments in the vicinity of these volcanoes. For instance, magnetic measurements could be used to differentiate which of the volcanic ash layers found in North Sumatera belongs to Mount Sinabung.