Ohio Assessment for Educators (OAE) Integrated Science (024) Practice Exam

Which volcano type is known for having a broad, gently sloping profile?

1. Composite volcano

2. Cinder cone volcano

3. Shield volcano

4. Fissure volcano

The correct answer is: Shield volcano

A shield volcano is characterized by its broad, gently sloping profile, which is primarily the result of the eruption of low-viscosity basaltic lava that can flow over great distances. This type of lava allows for the formation of gentle slopes, as it spreads out in a thin layer over the surface, unlike other volcano types that might produce more explosive eruptions or steeper profiles. The gradual build-up of layers from repeated lava flows contributes to the shield shape. In contrast, composite volcanoes generally feature steeper profiles due to the layering of more viscous lava and ash that results from explosive eruptions. Cinder cone volcanoes tend to be small and steep, created from the accumulation of volcanic debris and tephra. Fissure volcanism usually results in extensive lava flows that can form large plateaus rather than distinct mountain structures. Thus, the unique characteristics of shield volcanoes distinguish them as the type with broad, gently sloping profiles.