GEOLOGY

Detailed explanation-1: -Magmas with high silica content have a high viscosity (resistance to flow) and are generally more explosive when eruptions occur. All magmas also contain some degree of trapped gasses (CO2 & H2O ). The more trapped gas the more violent the explosion.

Detailed explanation-2: -Because volcanic magma becomes more silica-rich with time, its explosive potential increases.

Detailed explanation-3: -MAGMA COMPOSITION AND ROCK TYPES The magma types vary from mafic magmas, which have relatively low silica and high Fe and Mg contents, to felsic magmas, which have relatively high silica and low Fe and Mg contents.

Detailed explanation-4: -Because it is more difficult for dissolved gas to escape from more viscous magma, higher silica magmas generally erupt more explosively.

Detailed explanation-5: -Stratovolcanoes are more likely to produce explosive eruptions due to gas building up in the viscous magma. Andesite (named after the Andes Mountains), is perhaps the most common rock type of stratovolcanoes, but stratovolcanoes also erupt a wide range of different rocks in different tectonic settings.