Volcanoes Flashcards
(41 cards)
Weak spots in the earth’s crust through which molten material (magma) moves onto the surface
Volcanoes
Layer within earth’s mantle where temperature and pressure are high enough to melt rocks
Asthenosphere
Volcanoes are commonly formed along…
Plate Boundaries
Area over a mantle plume or under the crust where magma is hotter than surrounding magma
Hot Spots
How are volcanoes formed through hot spots?
Magma rises up through crust and forms a volcano, when the plate moves, the volcano is carried away from the hotspot becoming inactive, and new volcanoes can form
It is a well-known example of islands formed by a volcanic chain coming from hot spots
Hawaiian Islands
This active volcano is currently located above the Hawaiian Islands’ hot spot
Mount Kilauea
Molten material INSIDE a volcano
Magma
Molten material after reaching the earth’s surface
Lava
It is where magma is collected inside the earth
Magma Chamber
Bowl-shaped basin at the top of a volcano
Crater
Main passageway for magma to escape
Main Vent
Smaller outlets for magma to escape
Secondary Vents
Classifications of Volcanoes according to activity
- Active
- Potentially Active (dormant)
- Inactive (Extinct)
A volcano expected to erupt or is already erupting
Active
A volcano that isn’t erupting and isn’t predicted to erupt in the near future
Potentially Active (Dormant)
A volcano not expected to ever have another eruption
Inactive (Extinct)
How long ago does a volcano’s last eruption have to be before being considered extinct?
10,000 years
Types of Volcanic Eruption
Effusive and Explosive
Type of eruption wherein lava flows out of the crater and drifts into the volcano’s base without too much volcanic materials in the air
Effusive Eruption
Type of eruption wherein magma and other pyroclastic materials are expelled into the air
Explosive Eruption
Types of Lava Flow
Aa and Pahoehoe (pronounced pahoyhoy)
Blocky, rough lava flow
Aa Flow
Fluid lava flow, appearing in smooth thin broad sheets
Pahoehoe Flow
