EV 4

True or False. Most of the surface features of the Earth are there because of a plate tectonics reason.

True

True or False. Transform plate boundaries are where plates slide against one another.

True

True or False. We know where plate boundaries are, so we know where to expect plate movements.

True

The heat in the Earth's core comes from _____.

radioactive decay

We've learned a lot about the Earth's crust and interior from studying _____.

seismic waves from earthquakes

Plate tectonics is a way for the Earth to _____.

shed extra heat

The San Andres Fault is located on a _____ boundary between the Pacific and North America plates.

transform

The _____ are where plates are being destroyed in the Earth's mantle.

trenches

Some planets have lost plate tectonics because they _____.

have a cold, solid core

Convection describes the basic physics of ______.

hot materials rising and cold materials sinking

A seamount is different from a volcano. It is ______.

inactive, and remains under the surface

The _____ are where 60-80% of the Earth's surface is being formed.

mid-ocean ridges

Active deformation of the Earth's crust takes place at _____.

plate boundaries

The Earth's crust is mostly _____, its mantle _____ and its core, _____.

quartz & feldspar, olivine, iron

True or False. Divergent plate boundaries are where plates collide.

False

True or False. The Earth has finally cooled off completely to a uniform temperature after 4.5 billion years.

False

True or False. The cause of tectonic activity is finally well understood.

False

True or False. The same material is denser when it's hot than when it's cold.

False

There are basically _____ types of earthquakes.

Two

Volcanic island arcs are almost always associated with _____.

trenches

True or False. We currently have computer models that can predict what the surface of the Earth will look like 50 to 100 million years in the future.

true

Divergent plate boundaries are where the lithosphere is being rifted apart. What fills in the area of the rift?

volcanic activity

Plates slip past each other at _____ boundaries.

transform

True or False. Convergent plate boundaries are where plates collide.

True

The thinnest part of the Earth is the _____.

crust

The Hawaiian Islands are being formed as a plate _____.

moves over a hot spot

The topographic expression of a mid-ocean ridge system is a _____.

10,000 foot high volcanic mountain range

Trenches formed subducted plates at convergent boundaries can reach depths of up to _____.

6 kilometers

True or False. Because of plate tectonics, the Earth and Venus look very similar.

False

True or False. Earthquake tomography shows that subducting plates and associated earthquakes rarely reach depths beyond 600 meters in the mantle.

False

True or False. Earthquakes always occur at plate boundaries.

False

True or False. Geologic sciences community is in agreement about convection and its role in plate tectonics .

False

After seafloor spreading goes on for a hundred million years or so you can end up with _____.

a really big ocean

When two pieces of lithosphere collide and grind against each other at a subduction zone, pent up strain energy can be suddenly released as ____.

an earthquake

The vast majority of earthquakes occur _____.

at plate boundaries

The shallowest earthquakes occur _____.

at spreading ridges

The most violent earthquakes occur _____.

at subduction zones

Plates come together at _____ boundaries.

convergent

The Andes Mountains are the result of a _____ boundary.

convergent

Plates are pulling apart at _____ boundaries.

divergent

There's an extremely active boundary in East Africa, the Gulf of Aden and the Red Sea, where the continent is literally being torn apart. It is a _____ boundary.

divergent

Albuquerque, New Mexico sits on a boundary that could eventually place it _____.

in an ocean basin

Transform boundaries usually have _____.

only earthquakes

When there is subduction, one plate sinks under another, creating _____.

only earthquakes, volcanism, a trench and high mountains

Old pieces of ocean crust can sometimes sink to the deepest levels of _____

the Earth's core