1. Shield Volcanoes (Gentle-Sided)
* Shape: These volcanoes have a wide, gently sloping base that resembles a warrior's shield. They are built up by layers of very fluid lava flows.
* Eruptions: They erupt with effusive, non-explosive eruptions. This means the lava flows smoothly and easily, covering large areas.
* Lava Type: The lava is typically basaltic, which is very fluid and has a low viscosity.
* Examples: Mauna Loa in Hawaii, Kilauea in Hawaii, and the volcanoes of Iceland.
2. Composite Volcanoes (Steep-Sided)
* Shape: These volcanoes are tall, cone-shaped structures with steep sides. They are built up by layers of lava flows, ash, and volcanic debris.
* Eruptions: They erupt explosively, with alternating phases of lava flows and explosive eruptions.
* Lava Type: The lava is typically andesitic or dacitic, which is more viscous than basaltic lava.
* Examples: Mount Fuji in Japan, Mount Vesuvius in Italy, Mount St. Helens in the United States.
Here's a breakdown of the key differences:
| Feature | Shield Volcanoes (Gentle-Sided) | Composite Volcanoes (Steep-Sided) |
|---|---|---|
| Shape | Wide, gently sloping base | Tall, cone-shaped with steep sides |
| Eruptions | Effusive, non-explosive | Explosive, alternating lava flows and eruptions |
| Lava Type | Basaltic (fluid) | Andesitic or dacitic (viscous) |
| Examples | Mauna Loa, Kilauea, Icelandic volcanoes | Mount Fuji, Mount Vesuvius, Mount St. Helens |
Important Note: While shield volcanoes are typically associated with gentle slopes, some can also have steeper slopes, particularly on their flanks. However, their overall profile is still wider and less steep compared to composite volcanoes.
