Chapter 12: Earth's Internal Processes

Tension Stress

Tension Stress

A(n) ________, in which an object is stretched or lengthened.

Torsion Stress

A(n) ________, in which an object is twisted.

Elastic Rebound

________: The sudden release of strain energy when rock moves along a fault.

Earthquakes

________ are caused by forces that act on rocks.

Convergent Boundaries

________: Where plates come together.

Fault

A(n) ________ is a crack in Earths crust along which rock has moved.

Epicenter

________: The point on Earths surface directly above the focus.

Subduction

________: the oceanic side bending and being forced downward beneath the continental slab.

Rift Valley

________: long, linear, dropped- down valley between twin, parallel mountain ranges produced by faulting.

Hot Spots

________ are volcanically active sites that occur in places where large quantities of magma move to the surface in large, column- like plumes.

Plate motion

________ is caused by a combination of forces.

Plate Boundaries

Many volcanoes occur on Earth along ________, over hot spots, or in rift valleys.

seismic waves

To study Earths interior, geologists use ________.

Solid Materials

All ________ expelled by a volcano are collectively called pyroclasts.

Divergent Boundary

________: The boundary between two plates that are moving apart.

Mohorovicic Discontinuity

The ________ separates Earth's crust.

Volcanic Eruptions

________ can expel a variety of materials.

Mantle Material

Friction between a plate and ________ below the plate probably has a major effect on plate motion.

Discontinuity

________: The boundary between two layers of material that have different densities.

Liquid Magma

________ is less dense than the surrounding rock and is forced upward.

Cinder Cone Volcanoes

________: When the primary eruptive products are large fragments of solid material; tend to be small, with most cones having heights in the hundreds of meters range.

Composite Volcanoes

________: formed from alternating highly explosive events that form pyroclastic materials, and lava flows; composed of alternating layers, are large, often thousands of meters high and tens of kilometers across the base.

S waves

________ can not travel in Earth's liquid outer core, but P- waves pass through the outer core and the solid inner core.

earthquake

When a(n) ________ occurs, seismic waves spread out and travel through Earth.

volcano

A(n) ________ is a feature that forms when magma reaches the surface.

Wegener

________ hypothesized that the continents were moving by pushing through the ocean floor.

Magma

________ that has erupted onto Earths surface is called lava.

Earthquake

A(n) ________ is the sudden movement or vibration of the ground that occurs when rocks slip along enormous cracks in Earths crust.

Rift Valley

long, linear, dropped-down valley between twin, parallel mountain ranges produced by faulting

Divergent Boundary

The boundary between two plates that are moving apart

Convergent Boundaries

Where plates come together

Subduction

the oceanic side bending and being forced downward beneath the continental slab

Transform Boundaries

the horizontal motion of two plates past each other

Elastic Rebound

The sudden release of strain energy when rock moves along a fault

Focus

point of origin of an earthquake

Epicenter

The point on Earths surface directly above the focus

Discontinuity

The boundary between two layers of material that have different densities

Asthenosphere

weaker, plasticlike layer upon which Earths lithospheric plates move

Viscosity

a measure of the resistance of a fluid to flow

Cinder Cone Volcanoes

When the primary eruptive products are large fragments of solid material; tend to be small, with most cones having heights in the hundreds of meters range

Shied Volcanoes

form from high-temperature, fluid, basaltic lava and erupt with abundant lava flows that can move for kilometers over Earths surface before stopping; broad, flat structures made up of layer upon layer of lava

Composite Volcanoes

formed from alternating highly explosive events that form pyroclastic materials, and lava flows; composed of alternating layers, are large, often thousands of meters high and tens of kilometers across the base

Transform Boundary

the horizontal motion of two plates past each other.

Focus

point of origin of an earthquake

Athenosphere

weaker, plasticlike layer upon which Earth’s lithospheric plates move.

Viscosity

a measure of the resistance of a fluid to flow.