What causes volcanic eruptions to vary in intensity?

The intensity of volcanic eruptions depends on factors such as magma composition, gas content, and pressure. Magma high in silica is more viscous and traps gases, leading to explosive eruptions like those at Mount St. Helens. Less viscous magma, low in silica, allows gases to escape easily, resulting in gentler eruptions like those in Hawaii. The eruption type is also influenced by the volcano’s structure and tectonic activity.