Mount Merapi, island are volcano located in the center of Java (Indonesia), lies upon the remnents of a volcano older than 400.000 years called Pre-Merapi. Sensu stricto Merapi is a very young volcano characterised by a rapid edification. Its history is divided into four periods (ancient, Middle aged, Recent and Historical Merapi).
The Toba depression in northern Sumatera is a complex structure, formed by repeated episodes of caldera subsidence and resurgence, strongly influenced by regional structure. The Toba depression, and the associated Toba Tuff, a widespread ignimbrite sheet which covers approximately 20.000km, are the result of three major eruptive events.
Merapi volcano is one of the most active volcanoes in the world and during the last 3000 yrs, it has been more or less continuously in eruption. Merapi volcano is a stratovolcano with a south-west facing horseshoe-shaped summit crater filled by a lava dome. Its composition rangers from basalt to basaltic andesite (52 to 56% SiO2) and it has high Al2O3 (18.5 to 20.2% wt) and medium to high K2O …
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