ABCTE Science Practice Exam – Comprehensive Practice Test & Study Guide

The type of volcano that is typically characterized by explosive eruptions is the composite volcano. These volcanoes, also known as stratovolcanoes, are formed from alternating layers of lava flows, ash, and other volcanic debris. Their explosive eruptions are largely due to their steep profiles and the viscous nature of the magma that feeds them.

The magma in composite volcanoes tends to be andesitic to rhyolitic in composition, which contains higher amounts of silica, leading to higher gas content and more viscous lava. This increased viscosity prevents gases from escaping easily, building up pressure until it is released explosively. Classic examples of composite volcanoes include Mount St. Helens in the United States and Mount Fuji in Japan, both renowned for their violent eruptions.

In contrast, cinder cone volcanoes typically have more mild eruptions that produce lava fountains, while shield volcanoes are characterized by their broad, gentle slopes and relatively non-explosive eruptions due to low-viscosity basaltic lava. Plug domes can produce explosive eruptions, but they are smaller and less common compared to composite volcanoes.