The Merapi Volcano Monitoring System

Merapi volcano has the most advanced and comprehensive monitoring system in Indonesia. Monitoring at the volcano started in 1920, when the Dutch East Indies government established the Vulkaanbewakingsdienst. Since then, monitoring, initially carried out visually, evolved rapidly using bespoke monitoring equipment and modern technology, and with intensive cooperation with scientists and institutions from abroad. At present, BPPTKG (Balai Penyelidikan dan Pengembangan Teknologi Kebencanaan Geologi) in Yogyakarta has the mandate for hazard mitigation and the task of monitoring and providing early warnings to save local communities at risk from eruptions of Merapi. In carrying out its duties, BPPTKG manages a monitoring network consisting of various techniques, including seismic, deformation, gas and temperature monitoring, visual observations and attempts to improve monitoring techniques and methods, data handling and ways to provide early warning information. One of the fundamental recent changes in the Merapi monitoring system has been the transition in data processing from off-line-based to real-time, on-line-based techniques. Although the current Merapi monitoring system is presently at its most advanced, monitoring and anticipating changes in eruption styles, particularly those with weak precursors, such as phreatic eruptions, remain challenging.