Subsurface structures of Sianok Segment in the GSF (Great Sumatran Fault) inferred from magnetic and gravity modeling

Among the 19 segments of Great Sumatran Fault (GSF), Sianok segment is unique due to its proximity active volcanoes as well sizable Maninjau Caldera. Located next Sumani southeast, also passes through a relatively densely populated area. To identify potential disasters in future, it imperative understand subsurface structures segment. In this study, ground magnetic measurements were conducted, and data combined with Bouguer anomaly map. Hand samples collected measured for susceptibility density. The values later used initial parameters modeling. Joint forward modeling gravity was then stage interpretation stage. Subsurface models 20 km depth formulated based on data. show shallow magma chambers beneath Caldera, Mount Marapi, Singgalang-Tandikat. confirm that exposed unexposed Permian metamorphic rocks are commonly distributed thickness volcanic deposits such tuff andesites found be sizable, ranging from 1 3.5