Science Olympiad Dynamic Planet Practice Test

Which type of volcano tends to be more common in oceanic settings?

1. Stratovolcanoes

2. Shield volcanoes

3. Cinder cones

4. Subglacial volcanoes

The correct answer is: Shield volcanoes

Shield volcanoes are indeed more common in oceanic settings due to their formation process and the tectonic environment in which they typically occur. These volcanoes are primarily built up by the flow of low-viscosity basaltic lava that can travel long distances, creating broad, gently sloping sides that resemble a warrior's shield. In oceanic settings, particularly at mid-ocean ridges and hotspots like those found in Hawaii, shield volcanoes arise from the upwelling of magma as tectonic plates diverge or as mantle plumes rise. The basaltic composition of the lava in these areas is conducive to the creation of shield volcanoes, as it is less viscous than other types of lava, allowing it to spread out over wide areas. Additionally, the underwater environment facilitates the growth of these volcanoes, often beginning as submarine eruptions that can later emerge above sea level. In contrast, other types of volcanoes, like stratovolcanoes or cinder cones, tend to form in continental settings or on land, and may have different eruption styles and lava compositions that are less prevalent in oceanic environments.