Characteristics of Active Volcanoes in Sumatra, Indonesia: from Perspective Seismicity, Magma Chemical Composition and Eruption History

The characteristics of active volcanoes in Sumatra have been summarized based on the analysis
of the relationship between seismicity, morphology, magma chemical composition, and eruption history.
The level of volcano activity is linked to how partial melting depth, continuity distribution of hypocentre
beneath each volcano to the trench line (magma dyke), visual activity seen on craters, chemical magma
content, and reoccurrence of eruption analysis. The analysis result showed the current status of the volcano
is inverted linear with partial melting depth. The scatter point of the hypocentre beneath the alert and warning
volcano is continued to the trench line, but normal volcano status is discontinued. It was similar to volcanic
activity seen in craters. It may relate to the quantity and activity of magma flow in dyke. According to
reoccurrence analysis, Mt. Krakatau, Mt. Marapi, and Mt. Kerinci are highly vulnerable because they have
the shortest accumulated eruption interval. However, all of active volcanoes have the potential for repeated
massive eruptions, like what happened to Sinabung. Mix eruption is their eruption because magma types
tend to be basaltic and andesitic. Only on Mt. Dempo is detected rhyolitic (SiO2 more than 65%).