Shield Volcanoes
Shield volcanoes are a type of volcano characterized by their low, broad profile. They are primarily built up from numerous eruptions of fluid lava flows, which spreads out in all directions from a central vent, creating a shield-like shape. These volcanoes are commonly found in hot spot areas such as Hawaii, and are known for their relatively gentle eruptions compared to other types of volcanoes.
Formation of Shield Volcanoes
Shield volcanoes are formed by the accumulation of basaltic lava flows. The low viscosity of basaltic lava allows it to flow more easily, resulting in the gradual buildup of broad, gently sloping volcanic edifices over time. As the lava flows out of the central vent, it spreads over a wide area, creating the shield-like shape that gives these volcanoes their name.
Structure of Shield Volcanoes
Shield volcanoes are characterized by their low, broad profiles with gentle slopes. The central vent is typically located at the summit of the volcano, and the flanks are formed by layers of solidified lava flows. The calderas of shield volcanoes are relatively small and shallow compared to other types of volcanoes, and are often formed by the collapse of the summit due to the withdrawal of magma during an eruption.
Study Guide
When studying shield volcanoes, it is important to understand the following key points:
- The formation process of shield volcanoes, including the role of basaltic lava flows.
- The distinctive characteristics of shield volcanoes, such as their low, broad profiles and gentle slopes.
- The differences between shield volcanoes and other types of volcanoes, such as stratovolcanoes and cinder cone volcanoes.
- The locations where shield volcanoes are commonly found, such as hot spot areas and divergent plate boundaries.
- The potential hazards associated with shield volcanoes, including lava flows and gas emissions.
