Science Olympiad Dynamic Planet Practice Test

Which volcano is characterized by low-viscosity lava that can flow a great distance?

1. Stratovolcanoes

2. Shield volcanoes

3. Cinder cones

4. Cryptodomes

The correct answer is: Shield volcanoes

The type of volcano characterized by low-viscosity lava that is capable of flowing over great distances is the shield volcano. The key feature of this volcano type is its broad, gently sloping shape, which is formed by the eruption of low-viscosity basaltic lava. This lava can travel far from the eruption site before it cools and solidifies, allowing the volcano to grow larger in area rather than height. Shield volcanoes are primarily built from multiple layers of this fluid lava, which allows them to spread out, creating the shallow slopes that define their characteristic shape. The low viscosity of the lava means that it can easily flow over and around obstacles, filling in depressions and creating extensive lava fields. In contrast, stratovolcanoes, which are characterized by steeper slopes, often have more viscous lava that doesn't flow as easily and tends to build up in the form of explosive eruptions. Cinder cones are generally small, conical-shaped volcanoes that erupt lava in a more viscous state, leading to more localized and steeply-sloped structures. Cryptodomes are formations that are created when magma intrudes into the surface but does not erupt, leading to bulging rather than flowing. Thus, the distinction in lava composition