Volcanism Flashcards
What is magma?
A: Molten rocks (that contain SI, Al, NA, Ca, Mg, Fe etc) if the temperature is high enough (600F) rocks melt like wax
What is the physical composition of magma?
A: Although we call magma a liquid, most magma has solids (minerals already formed ) and gases
What is volcanism?
A: Arrival of magma at the earth’s surface.
What is a volcano?
A: a feature formed by volcanism. Volcanos typically look like cones
Where do volcanoes form?
A: they form above locations where rocks melt due to excessive heat.
What is a vent?
A: the opening where magma or gasses come out from.
What is a caldera?
A: a depression formed by the collapse of the top of the volcano after eruption is complete
What is a rim?
A: the outer circular edge of the Caldera.
How many active volcanoes are in the world?
A: there are 1500 active volcanoes in the world.
How many volcanoes ruptured in the last 100 years?
A: 100
How many volcanoes erupt every year?
A: 50 volcanoes erupt every year
Is magma less dense or more dense?
A: less dense. It rises to the top of a volcano
What happens during the rise of magma?
A: gases separate from the magma
What happens if the gases escapes from the magma?
A: then the magma flows calmly out of the vent. (Hawaiian-Style)
What happens if the gases are trapped in the magma?
A: the pressure in the volcano builds up and the volcano explodes like a high powered bomb. ( Strombolian-Style)
Where are volcanoes found?
A:Most volcanoes are found near old or new (active) plate boundaries. Some volcanoes are formed above hotspots
What are the types of magma?
A: Felsic (granitic), intermediate (andesitic), mafic ( Basaltic) and ultra mafic.
What is the classification of felsic magma and its eruption style?
A: rich in SIo2, high in viscosity, and the eruption style is explosive( ash)
What is the classification of intermediate
(Andesitic) magma and eruption style
A: rich in Intermediate, viscosity intermediate, eruption style explosive
What is the classification of mafic (basaltic) magma??
Rich in Fe, Mg viscosity low, eruption style calm (lava)
What is the classification of ultra mafic magma?
A: rich in only Fe-Mg, viscosity very low, eruption style not found today.
What is the classification of lava?
A: flowing magma, found in low elevations and its slow.
What is the classification of lahars?
A: Mud flows (snow melts and ash) and it has fast speed
What’s the classification of gasses?
A: contains H20 CO2 SO2 etc, found everywhere and it’s speed is slow
