The Solid Earth - Chapter 7: Volcanoes and Volcanic Eruptions Flashcards
Successive eruptions from a central vent result in a mountainous accumulation of material known as a _____
volcano
This is located at the summit of many volcanoes and is a steep walled depression connected to a magma chamber via a pipelike conduit or vent
crater
This is the name for summit depressions that exceed one km in diameter
calderas
Lava that is very _____ creates a plug in the pipe which rises slowly or is blown out, often enlarging the crater
viscous
Sometimes it is easier for magma or escaping gasses to push through _____ on the volcano’s flanks
fissures
Continued activity from a flank eruption may build a “______”
parasitic cone
The name for secondary vents that only emit gases
fumeroles
Name the three types of volcanoes
Shield
Cinder
Composite
These volcano types form when fluid lava is extruded and the volcano takes on a shape of a broad domed structure. These are made primarily of basaltic lava flows and contain only a small percentage of pyroclasts
shield
Which type of volcano is built from ejected lava fragments?
Cinder cones
Cinder cones have a very (gentle/steep) slope
steep
What are two names for earth’s most picturesque volcanoes?
composite cones
stratovolcanoes
Most active composite cone volcanoes are located in a narrow zone that encircles the Pacific Ocean called
Ring of Fire
A composite cone is a large and nearly ____ structure built of interbedded lavas and pyroclastic deposits emitted mainly from a central vent
symmetrical
Composite cones are produced when relatively viscous lavas of andesitic composition are ____
extruded
True or false: the composite cone is only known for extruding lava for long periods
False; it can also change to host a violent eruption of pyroclastic material
What is the most violent type of volcano?
composite cone
Which type of volcano destroyed Pompeii and was named Vesuvias?
Composite cone
eruptions of a devastating nature that happen when hot gases infused with incandescent ash are ejected creating a fiery cloud referred to as a glowing avalanche
nuee ardente
Which causes faster destruction: a violent explosion or a glowing avalanche?
Glowing avalanche
The name of a mudflow that composite cones can generate
lahar
Most volcanoes are fed by conduits called ____ or ____
pipes
vents
What are pipes or vents believed to connect to?
A magma source
The materials in the vents are considered to be representative samples (windows) of the ___
asthenosphere
______ are easily eroded because they are composed of unconsolidated materials
cinder cones
The remaining structure occupying the vent that does not weather as quickly after the rest of the volcano has eroded
volcanic neck
