Vocab
is the opening of a volcano
vent
How many types of volcanoes are there?
3
What is the relationship between magma and lava?
Lava is magma that has reached Earth’s surface.
What is created when lava cools and hardens beneath the earth's surface?
What is an igneous intrusion?
is magma that has reached Earth’s surface
lava
Which volcano is built by alternating layers of lava and ash and can create explosive eruptions?
What is a composite volcano
Where would molten material, ash, and dust be expelled?
vent
What is important about the Ring of Fire? Why do so many volcanoes form in this region?
The Ring of Fire is a place where many volcanoes form because of plate tectonic activity surrounding the Pacific Plate.
melted rock which is less dense than solid rock, so it rises to the surface
magma
are volcanoes with broad bases and gently sloping sides. They are the result of mild eruptions.
shield volcanoes
What is the most active volcanic region?
What occurs to allow the caldera to form?
A caldera forms when an underground magma chamber empities and the land above collapses into the empty chamber, forming a cauldron-shaped depression on Earth’s surface.
any place where gas, ash, or melted rock come out of the ground
volcano
What kind of volcano is small with steep angled sides, is built over a small period of time, and spits lava which falls on the sides of the volcano called?
cinder cone volcano
How does pyroclastic material differ from lava?
Unlike lava, pyroclastic material is associated with explosive eruptions.
How does a new crust form at divergent boundaries?
As tectonic plates spread apart, older, thicker crust moves away from the plate boundary. In the area of thinner crust, the pressure drops and partial melting generates magma, which rises up from the mantle. Some of this magma may erupt through cracks onto the sea floor to make new crust.
are giant sections of lithosphere on Earth’s surface
tectonic plates
Which type of volcano has the steepest sides?
composite volcanoes
A hot spot is a volcanically active area.Which would you expect to find beneath the hot spot?
1. a rift zone
2. a mantle plume
3. a divergent boundary
4. a convergent boundary
A mantle plume
What are the three different types of volcanoes? Describe each.
Shield Volcanoes are Volcanoes with a broad base and gently sloping sides. They cover a wide area and generally form from mild eruptions. Layers of lava flow out from the vent, harden, and slowly build up to form the cone. The Hawaiian Islands are shield volcanoes.
Cinder Cones volvanoes are where ash and pieces of lava harden in the air and can fall to the ground around a small vent. The hardened pieces of lava are called cinders. The cinders and ash build up around the vent and form a steep volcano called a cinder cone. A cinder cone can also form at a side vent on other volcanic mountains.
Composite Volcanoes are where alternating layers of hardened lava flows and pyroclastic material create composite volcanoes. During a mild eruption, lava flows cover the sides of the cone. During an explosive eruption, pyroclastic material is deposited around the vent. Composite volcanoes commonly develop into large and steep volcanic mountains.