The municipality of San José de Maipo is located in the northern part of the southern volcanic area of the Andes, in an approximately 120 km wide volcanic arc. The arc contains basins and volcanoes and it extends over Chile and Argentina.
This area comprises three volcanic complexes (Tupungato – Tupungatito, San Jose – Marmolejo and Maipo), which form a narrow north-south chain on the border between Chile and Argentina, about 290 km away from the deep sea trench (Stern, 2004).
The earth’s crust is relatively thick here, the magmas is rich in silica and eruptive / explosive materials (SEGEMAR, 2008).
