Volcanoes Short Questions Flashcards
Where do volcanoes occur
- Mid ocean ridges - constructive plate margins
- Subduction zones - destructive
- Hotspots
Example of a volcano at a mid ocean ridge
Mount Hekla Iceland on mid Atlantic ridge
Example of a volcano at destructive plate margin
Nevada del Ruiz as Nazca and S.A collide
Example of a hotspot
Hawaiian islands
Define active volcano
Continuously erupting - Mount Etna Italy
Define dormant volcano
Has not erupted in many hundreds of years but expected to erupt in future e.g Mt St Helens in US dormant for 123 years
Define extinct volcano
Not erupted in recorded history - Slemish Co.Antrim
How much silica in acid lava
70% or more
Makes lava highly viscous and traps gases
Very explosive - Mt St Helens
How much silica in basic lava
Less than 55%
Few trapped gases as lava runny
Gentle eruption - Mauna Loa Hawaii
What volcanic dome shape forms due to acidic lava
Dome - at destructive boundaries
What volcanic dome shape forms from basic lava
Shiela volcano - constructive and hotspots
What gases do volcanoes release
Co2, chlorine, sulfur dioxide
Example of a extrusive lava plateaux
Antrim Plateau in NI
Example of a volcanic cone
Mouth Etna
Example of a volcanic plug
Le Put France
