Volcanic Eruptions Quiz

Volcanoes

• Volcanoes are classified by morphology (shape) and activity.
• Cinder cones are formed by ejected lava. They are short-lived and have a steep, cone-shaped structure.
• Shield volcanoes are created by the flow and layering of fluid lava. They are low and broad, with gently sloping sides.
• Composite volcanoes, also called stratovolcanoes, are built up by layers of viscous lava, ash, and rock. They have steep sides.

Types of Volcanic Activity

• Active volcanoes have shown recent activity (within the last 10,000 years).
• Dormant volcanoes haven't erupted recently but could erupt again in the future.
• Extinct volcanoes are unlikely to erupt again.

Magma Formation

• Magma is semi-molten rock that rises from the Earth's mantle.
• Magma formation happens at convergent boundaries where one tectonic plate moves under another, or due to decompression melting.

What is a Volcano

• A volcano is an elevated landform with an opening called a crater, from which lava, rock fragments, steam, gases, ash, heat, and other volcanic materials are ejected.

Parts of a Volcano

• Crater - the vent opening of a volcano.
• Parasitic cone - a small opening around the vent where volcanic materials can escape.
• Ash cloud - a cloud of ash formed during eruptions.
• Vent - an opening in the Earth's surface through which volcanic materials escape.
• Conduit - an underground passage through which magma travels.
• Lava flow - a mass of molten rock ejected during an eruption.
• Volcanic bombs - fragments of molten rock ejected during an eruption.
• Magma chamber - a large underground pool of liquid rock beneath the surface.
• Flank - a side of the volcano.
• Multiple layers of lava and ash -layers of solidified lava and the material ejected during an eruption.

Eruption Types

• Hawaiian eruptions are characterized by highly fluid lava flowing out of several vents.
• Strombolian eruptions involve the continuous ejection of magma and gas, creating volcanic bombs and cinder cones.
• Vulcanian eruptions are characterized by thick viscous magma and a dense cloud of ash-laden gas, often starting with phreatomagmatic eruptions.
• Plinian eruptions are the most violent. They involve the build-up of viscous magma and dissolved gas, accompanied by fast-flowing pyroclastic debris and lahars.

Volcanic Hazards

• Ash cloud blasts occur from hot bursts of trapped gases.
• Volcanic gases are released from active and inactive volcanoes. These include water vapor, carbon dioxide, hydrogen gas, hydrogen chloride, hydrogen fluoride, hydrogen sulfide, and sulfur dioxide..
• Lava flow refers to the movement of molten rock down the slopes of volcanic vents.
• Pyroclastic flows are glowing hot materials travelling down the slope of an erupting volcano after contact with the ground.
• Pyroclastic surge refers to the ejection of volcanic materials (gases, ash, rock fragments, water) above the ground.
• Lahars are mudflows or flows of volcanic debris, which can be primary (hot) or secondary (cold).
• Various other results, namely, dome growth, Tephra, and tsunami.