Chapter 21

Granite does not readily form near oceanic-oceanic convergent boundaries because

-oceanic-oceanic convergence often results in the eruption of an andesitic lavas

Evidence to support the fact that Earth's center core is solid can be attributed to

An increase in P wave velocity as they encounter and move through the inner core

The theory of continental drift is supported by paleoclimatic data, the jigsaw fit of the continents

At their continental margins, and paleontology

Tensional forces cause the crust to

Break and fracture thereby lengthening the crustal surface

In comparison to P-waves, S-waves

Can travel only through solids not fluids

The Mohorovicic discontinuity occurs because of a

Change in the composition of rocks on both sides of the boundary

Earth's magnetic field is not stable; throughout geologic time it has changed direction. The change is attributed to

Changes in the direction of fluid flow in the molten outer core of earth

The lithosphere includes

Continental and oceanic crust and the upper part of the mantle

Volcanoes do not form at which type of convergent plate boundary?

Continental- continental convergent boundaries

Water causes partial melting of the mantle at which type of plate boundary?

Convergent boundaries

Isostasy is

Crystal equilibrium relative to the mantle

Volcanic activity is associated with

Divergent and convergent boundaries

And anticline is a fault in which the limbs bend

Downward

Earth's Internal layers were discovered by studying the movement of P and S waves through earths interior. In comparison to S waves, the movement of P waves is

Fast, compressing and expanding the rock as they move through it

The theory of seafloor spreading is attributed to

Harry Hess

A tsunami is unlike most other water waves mainly because it

Has a very long wavelength

Detailed mapping of the ocean floors revealed

Huge mountain ranges on the seafloor, and deep trenches near some of the continents

The Mercalli scale measures an earthquakes

Intensity, damage and overall effect

The Mohorovicic discontinuity any marks the change in rock density elasticity between the

Mantle and the crustal surface

As hot mantle rock rises, it expands. As it expands it cools. This cooler rock is

More dense so it stinks. This contributes to the heat flow convection process.

Mountains tend to form in long narrow ranges is because

Of plate convergence- plates coming together

Which seismic waves produce a wave shadow?

P and S waves

The theory of seafloor spreading is supported by

Paleomagnetic analysis of the ocean's floor

We can say that earth's crust floats on the mantle because

Part of the mantle is hot enough to flow as a plastic solid

Plate tectonics differs from continental drift because it

Provides a credible driving force

When rock is subjected to compressive force, it may fault. If rocks in the hanging wall are pushed up over rocks in the foot wall, it is called a

Reverse fault

The concept of seafloor spreading states that

Seafloor is created at mid ocean ridges and destroyed at deep ocean trenches

The primary evidence that the outer core is molten is an abrupt

Stop of S-wave propagation, and a decrease in P wave velocity

The process in which one plate bends and sense beneath another plate is called

Subduction

The stress that occurs when material is pulled apart is called

Tensional stress

Evidence to support that the inner core is solid and the outer core is liquid comes from

The wave shadow effect of P and S waves, and increase of velocity of P waves as they encounter the solid inner core

According to platonic theory, the San Andrea's fault is a

Transform fault

The top of the mantle is the same as the

base of crust

The energy in an earthquake is released

before the quake, after the quake, and during the quake.

In a fold sequence of rocks, we find younger rocks at the axis of the fold and older rocks away from the fold axis. The fold is

called a syncline

Reverse faults are the result of

compression

An Earthquake occurs as

energy released from Earth's interior travels in the form of seismic waves to Earth's surface

The mantle is composed of

iron-rich silicate rocks

Motion of P-wave is

longitudinal

Secondary waves can travel through all areas of Earth except the

mantle

The asthenosphere is part of the

mantle

Spreading centers occur along

mid-ocean ridges

The San Andreas Fault in California is a

strike-slip fault

The dominant force at divergent boundaries is

tension

Divergent boundaries are areas of

tensional forces that stretch the crust and generate a spreading center

The speed of a seismic wave depends on

the type of material it travels through

The outer core is liquid because

there is less weight, and thus less pressure on it

The thickness of Earth's crust

varies from about 10 km under the oceans to about 60 km under the continents

Regions in which earthquakes are common are also regions in which

volcanoes are common

Wegner's Theory of Continental Drift

was not accepted by the scientific community of the early 1900s