Volcano Types | Volcanic Landforms

NZ volcanoes

RUNNY LAVA STICKY LAVA

EXPLOSIVE
Mt. Victoria (extinct)
• Fire fountain of lava
• Low cone, steep sides
• E.g. Mt Victoria, Mt Eden
• Produces scoria
Mt. Ruapehu (dormant)
• Big explosion – ash released
• Large volcano – strato
• E.g. Mt Ruapehu, Mt Taranaki
• Produces andesite, ignimbrite

NON-
EXPLOSIVE
Rangitoto (extinct)
• No explosion
• Wide cone, not high
• E.g. Rangitoto
• Produces basalt
Table Mountain (extinct)
• No explosion – ash released if magma reaches surface
• No cone – causes land to bulge
• E.g. Table Mountain in Coromandel, Warkworth Dome
• Produces granite

	RUNNY LAVA	STICKY LAVA
EXPLOSIVE	• Fire fountain of lava • Low cone, steep sides • E.g. Mt Victoria, Mt Eden • Produces scoria	• Big explosion – ash released • Large volcano – strato • E.g. Mt Ruapehu, Mt Taranaki • Produces andesite, ignimbrite
NON- EXPLOSIVE	• No explosion • Wide cone, not high • E.g. Rangitoto • Produces basalt	• No explosion – ash released if magma reaches surface • No cone – causes land to bulge • E.g. Table Mountain in Coromandel, Warkworth Dome • Produces granite

   Rule of thumb
   The higher the silica content, the stickier (more viscous) the magma/lava (flows fast if runny and slowly if sticky);
   the higher the gas content, the more explosive the eruption (gas escapes due to pressure change at vent causing material to be erupted explosively).

Pictures courtesy of Google Images; based on idea from Rhys Hodson (TGS)

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