A bowl shaped area that may form at the top of a volcano around the central vent.
What is a crater
Mountains that form in Earth's crust when molten material or magma reach the surface.
What is volcanoes
Forms after magma and lava cool.
What is rock
This type of eruption has a low silica lava and it oozes from the vent.
What is a quiet eruption
Smallest pieces of lava.
What is volcanic ash
The spread of lava as it pours out of a vent.
What is lava flow.
Molten mixture of rock-forming substances, gases, and water from the mantle.
What is magma
Volcanic belts form along the boundaries of Earth's what?
What are plates
Forms from fast moving, hot lava that is thin and runny. It looks like a solid mass of ropelike coils.
What is pahoehoe
Largest pieces of lava that range from the size of a golf ball to the size of a car.
What is a bomb
A pocket of magma beneath the surface.
What is magma chamber
What is an island arc
Most volcanoes form at which type of boundary?
What is convergent plate boundary
This type of eruption has a high silica magma and is thick. It builds up in the pipe, plugging it like a cork.
What is explosive eruptions
A volcano that is sleeping but that scientists expect to awaken in the future and become active.
What is dormant
Molten rock and gas leave the volcano through this opening.
What is the vent
Magma once it reaches the surface.
What is lava
An area where material deep within earth's mantle rises through the crust and melts to form magma.
What is a hot spot
Forms lava that is cooler and thicker and has a rough surface consisting of jagged lava chunks.
What is Aa
Geologists use this to detect changes in volcanoes to find warnings that they may erupt.
What is a tiltmeter
A long tube that extends from Earth's crust up through the top of the volcano.
What is the pipe
A major belt of volcanoes which rim the Pacific Ocean.
What is the Ring of Fire
These push magma from the magma chamber through the pipe until it flows or explodes out of the vent.
What are expanding gases
This volcano is known for its explosive eruption in 1980.
What is Mt St Helens
The name for volcanoes that are no longer over a hot spot.
What is an extinct volcano