Explain How Different Plate Boundaries Influence the Form, Frequency and Type of Volcano

Explain how different plate boundaries influence the form, frequency and type of volcano…
The constructive plate margin (divergent) occurs when the plates move apart. Volcanoes are formed and magma wells up to fill the gap, and eventually new crust is formed. The type of magma that is produced here is basaltic lava which is made from silica; this more fluid and runny (like syrup). The lava characteristics at a constructive plate margin has little violence as it allows gas bubbles to expand on the way up to the surface; preventing a less explosive activity. The materials that are erupted are mainly lava. The frequency of the eruption time is regular and can be continuous. The form of the volcano has a low lying shape, called a shield volcano. This is formed from the free flowing lava. The resulting volcanoes have gentle sides and cover a large area, an example of this is Mauna Loa in Hawaii.
The destructive plate margin (convergent) occurs when oceanic and continental plates move together. The oceanic plate is forced under the lighter (less dense) plate; Friction causes melting of the oceanic plate and may trigger earthquakes. Magma rises up through cracks and erupts onto the surface. The type of magma that is produced here is acidic which is called rhyolitic. This is magma that is very viscous (thick); it solidifies before reaching the surface, leading to build-up of pressure and violent explosion. The lava characteristics here are very slow flowing as it is very viscous. The type of eruption here is potentially explosive; as the lava shatters into pieces. The materials erupted at a destructive volcano are lava bombs, ash and dust. The frequency of eruption time is ‘from time to time’, long dormant periods. The form of the volcano is an acid lava dome composite cone. It is formed of layers of lava and ash. This is because it creates a new layer due to magma that has been erupted and solidifying straight after.