Abeka 6th grade Science test 5

Earthquake

Any trembling or shaking of the earth's crust

Epicenter

The place at ground level that is directly above the focus of an earthquake

focus

The point underground where an earthquake begins

Fault

A break that appears at the boundary between two moving masses of rock

Tsunamis

Earthquakes sometimes cause monstrous waves

Magnitude

The strength of an earthquake

Volcano

Allows molten rock and hot gases to escape from within the earth

Increases

The temperature of rocks ____________ with depth..

Vent

Created when trapped gases blast through the earth's surface.

Chemical Weathering

Occurs when natural acids slowly eat into a rock, breaking it apart.

Tephra

Smaller fragments of molten rock that solidify almost instantly

Fumaroles

Holes or cracks which serve as escape vents for underground gases

Crater

A depression found at the top of a volcano

Ring of Fire

Running along the edge of the Pacific Ocean; named for its many volcanoes

Lava

Magma that has reached the earth's surface

Dormant

A volcano that has been active at some time in recorded history, but has not had a recent eruption

Hawaiian

A volcano that produces lava fountains or fire curtains

Plinian

A volcano characterizied by hot clouds of gas and dust that it expels

Active

A volcano that has erupted recently

Extinct

A volcano that has not erupted in recorded history

Geologists

Scientists who study the structure of the earth

Weathering

The process by which new soil is formed as rocks crumble and break into smaller pieces

Moho

The boundary between the earth's crust and its mantle

Mid-oceanic ridges

The underwater mountain ranges

Seismology

The study of earthquakes

crust

the thin and outermost layer of the earth

mantle

middle layer of the earth; makes up the largest portion of the earth interior; its made of solid rock

core

the innermost region of the earth; divided into two sections; are made of metals rather than rocks