Mount St. Helen's
All the processes associated with the discharge of magma, hot fluids, ash and gases is called
A. Hot Spots
B. Tephra
C. Pyroclastic Flows
D. Volcanism
D: Volcanism
A volcanoes explosivity depends on the composition of the volcanoes
A. Tephra
B. Pyroclastic Flows
C. Magma
D. Viscosity
C: Magma
Volcanoes that have previously erupted with a magnitude of eight on the volcanic explosivity scale are called...
A. Shield Volcanoes
B. Super Volcanoes
C. Composite Volcanoes
D. Cinder Cone Volcanoes
B: Super Volcanoes
The erupted materials (rock, ash, and lava) that are ejected out of the volcano during an eruption is called
A. Pyroclastic Flows
B. Hot Spots
C. Tephra
D. Viscosities
C: Tephra
Most volcanoes form where?
A. Inside Mountains
B. Tectonic Plate Boundaries
C. Hot Spots
D. In Earth's Crust
B: Tectonic Plate Boundaries
A mountain with broad, long, gently sloping sides and a nearly circular base. Made up of layers of solidified basaltic lava that accumulates during non-explosive eruptions.
A. Shield Volcanoes
B. Cinder Cone Volcanoes
C. Composite Volcanoes
D. Strato Volcanoes
A: Shield Volcanoes
Formed from layers of ash and hardened chunks of lava from violent eruptions. Are generally cone shaped with concave slopes. Are the most explosive volcanoes and potentially dangerous to humans and the environment.
A. Shield Volcanoes
B. Composite Volcanoes
C. Cinder Cone Volcanoes
D. None of the Above
B: Composite Volcanoes
Opening in the Earth's crust through which lava erupts and flows out onto the surface.
A. Caldera
B. Conduit
C. Vent
D. Cinder Cone
C: Vent
Volcanoes that form far from plate boundaries that are unusually hot regions of earth's mantle where high temperature plumes of magma rise to the surface are called
A. Shield Volcanoes
B. Silica
C. Hot Spots
D. Strato Volcanoes
C: Hot Spots
The physical property that describes a materials resistance to flow.
A. Viscosity
B. Tephra
C. Pyroclastic Flow
D. Hot Spots
A: Viscosity
Rapidly moving clouds of tephra mixed with hot, suffocating gases are called
A. Rhyolitic Magma
B. Volcanic Waves
C. Pyroclastic Flows
D. None of the Above
C: Pyroclastic Flows
Magma that has low silica content and low viscosity that allows gases to escape easily and results in quiet, non-explosive eruptions.
A. Rhyoltic Magma
B. Andesitic Magma
C. Pyroclastic Magma
D. Basaltic Magma
D: Basaltic Magma
A tube like structure that allows lava to reach the surface.
A. Vent
B. Crater
C. Caldera
D. Conduit
D: Conduit
Magma that has an intermediate silica content and intermediate viscosity which results in volcanoes that have intermediate explosivity.
A. Pyroclastic Magma
B. Rhyolitic Magma
C. Andesitic Magma
D. Basaltic Magma
C: Andesitic Magma
Volcanoes that have steep sloped sides, are coned shaped, and are the smallest of the three types of volcanoes. They have explosive eruptions and usually form at the edges of larger volcanoes.
A. Composite Volcanoes
B. Cinder Cone Volcanoes
C. Strato Volcanoes
D. Shield Volcanoes
B: Cinder Cone Volcanoes
Magma that has a high silica content and high viscosity resulting in gases becoming trapped in the magma which produces explosive eruptions.
A. Rhyolitic Magma
B. Basaltic Magma
C. Pyroclastic Magma
D. Andesitic Magma
A: Rhyolitic Magma
As the amount of gases in magma increases, the magma's explosivity
A. Increases
B. Decreases
C. Stays the Same
D. Both increases and Decreases
A: Increases
What is the deadliest and most destructive part of an explosive volcanic eruption?
Pyroclastic Flow
A bowl shaped depression that forms around the central vent at the summit of a volcano is called a..
A. Caldera
B. Lava Plateau
C. Crater
D. Tephra
C: Crater
A large crater that can form when the summit or side of a volcano collapses into the magma chamber during or after an eruption is called a....
A. Conduit
B. Lava Plateau
C. Caldera
D. Tephra
C: Caldera
Identify the reason rhyolitic magma produces explosive eruptions.
Magma has high silica content which results in magma that is very thick and sticky which traps gases and produces explosive eruptions.
Identify the reason why basaltic magma produces non-explosive eruptions.
Low silica content results in magma that is thin and runny. This allows gases to easily escape and produces non-explosive eruptions.
The amount of this molten material in magma determines how explosive the magma will be. What is the name of this molten material?
Silica
How can volcanoes affect climate?
Ash and dust from eruptions block the sunlight and lower temperatures.
Name one of the two major volcanic belts in the world.
1. Circum-Pacific Belt (Pacific Ring of Fire)
2. Mediterranean Belt