Plate Tectonics Questions
The main difference between a shield volcano and a stratovolcano lies in their shape and eruptive behavior.
A shield volcano is characterized by its broad, gently sloping sides and a relatively flat summit. It is formed by the accumulation of numerous thin lava flows that spread out over a large area. Shield volcanoes are typically found at hotspots or along divergent plate boundaries. They have relatively low viscosity lava, which allows it to flow easily and cover large distances. The eruptions of shield volcanoes are generally non-explosive and are characterized by the effusion of basaltic lava.
On the other hand, a stratovolcano, also known as a composite volcano, has a steep-sided conical shape. It is built up by alternating layers of lava flows, volcanic ash, and other volcanic materials. Stratovolcanoes are commonly found at convergent plate boundaries, where one tectonic plate subducts beneath another. They are associated with explosive eruptions due to the high viscosity of their magma, which traps gas and leads to explosive release. These eruptions can be highly destructive and produce pyroclastic flows, ash clouds, and volcanic bombs.
In summary, shield volcanoes have a broad, gently sloping shape and non-explosive eruptions with low viscosity lava, while stratovolcanoes have a steep-sided conical shape and explosive eruptions with high viscosity magma.