Due to this, Gunung Merapi became one of the best monitored volcanoes worldwide. The main three aims are explained by its name. We exist here in a country of the volcanoes. This applies to nature. This applies to the people, the nation.
Volcanoes can explode at any time.
Longterm continuous deformation measurements of the edifice of this Decade Volcano should be recorded to get knowledge about pressure changes within the volcano connected with changes in the magma system. Three stations form a ring to monitor deformation of the whole edifice of Merapi. The instruments are installed in boreholes at depths of 3 m to 4 m and horizontal distances of 50 m to 90 m to discriminate local and regional tilt events. Significant variations of the tilt signals verify the successful coupling of the tiltmeters and their surrounding and the high resolution of the instruments. The tide spectra also show the minimization of nearsurface meteorological noise, especially the temperature effect, by the installation in boreholes at adequate depths.