Abeka 8th grade Science section review 2.3

Magma

molten rock

What are the three common types of volcanoes by structure?

1. Cinder-cone volcanoes (loose, not as large, single eruption) 2. shield volcanoes (lots of lava, mild eruptions, gently sloping cone) 3. composite/stratovolcanos volcanoes (both cinders/lava, symmetrical, explosive eruptions, steeper than shield volcano)

Most of the world's volcanic belts are located in the same places as the earth's earthquake belts. Why might this be considered evidence for the theory plate tectonics?

According to plate tectonics theory, earthquake and volcano belts both are likely to occur at or near the boundaries between plates.

What term describes a volcano that will probably not erupt again?

An extinct volcano

What is a volcano?

An opening in the earth's surface through which hot gases, ash, and molten rock are ejected from the earth's interior.

how volcanologist predict eruptions

GPs; fly over volcanoes to sample gasses; microphones; 3D imaging; video cameras

What narrow zone encircling the Pacific Ocean contains over half of the world's active volcanoes?

The Ring of Fire

Define pyroclastic flow.

The pyroclastic flow consists of a super heated cloud of gas and volcanic ash that travels swiftly down the volcanic slope as an avalanche.

An example off the most violent of commonly occurring natural disasters

a volcano

What is a bowl-shaped thought to be caused by the collapse of an empty magma chamber?

calderas

vent or channel

central feature of a volcano through which gases, ash, and rock are ejected ("weak spot" in the earth's crust)

cinders

erupted volcanic ash and rock fragments

active volcano

has erupted within recorded history or is currently producing seismic activity

dormant volcano

inactive volcano that could erupt again

volcanologists

people who study volcanos

magma chamber

reservoir of magma beneath the ground; actual source of the eruption

volcanology

study of volcanoes

crater

A bowl-shaped area that may form at the top of a volcano around the central vent (often caps the cone)

Define igneous intrusion.

Mass of volcanic rock beneath the surface.

What is lava?

Molten rock that flows from volcanoes.

What are pyroclasts?

Particles or blocks of solid volcanic ejecta.