Please enable JavaScript.
Coggle requires JavaScript to display documents.
HAZARDS - Coggle Diagram
HAZARDS
-
VOLCANOES
TYPES OF VOLCANOES
The range of landforms produced by volcanic eruptions is related to:
- where and how the eruption takes place
- the type of lava (viscosity, how it flows)
- the materials produced (gas, ash, lava etc.)
EXPLOSIVE
These eruptions are violent because of built up pressure - viscous magma here prevents gas from escaping.
- Location - convergent plate boundary (plates moving towards each other.
- Lava Type - rhyolite (high acidity) and andesite (low acidity).
- Eruption Style - violent bursting gas bubbles, explosive vent and top of cone is often shattered.
- Materials - gas, dust, ash, lava bombs and tephra.
- Frequency - long periods with no activity, short destructive explosions.
- Volcano Shape - steep-sided stratovolcanoes - has calderas.
- Products - composite cone volcano, internal lava flows, calderas (when cone is destroyed).
EFFUSIVE
These are gentle free-flowing basic eruptions of lava.
- Location - divergent plate boundaries (plates move away from each other).
- Lava Type - basalt.
- Eruption Style - gas bubbles expand, limited explosion.
- Materials - gas and lava flows.
- Frequency - more frequent, duration can be for months.
- Volcano Shape - gentle sloped sides, shield volcanoes
- Products - magma flows freely, large magma coverage.
-
-