Earth Science Final

What is an isochron ?

a line on a seafloor map that connects points of equal range

What is a pyroclastic flow?

a mixture of volcanic gas, ash and other tephra

What is the name for an igneous intrusion that is smaller than a batholith but similar in shape?

a stock

An earthquake on the ocean floor can produce ______________________________

a tsunami

What is the name for a large crater formed when a magma chamber collapses?

caldera

What is the name of a large volcanic crater over 1 km in diameter?

caldera

What texture do most plutons have?

coarse

Where do most volcanoes form?

at plate boundaries

Where does an earthquake originate?

at the focus

Where is andesitic magma found?

at the margins of the continents

Where are the youngest rocks on the ocean floor located?

at the mid ocean ridges

What type of magma has the lowest silica content and is the least explosive?

basaltic

A _________________ is a large intrusive rock body that covers at least 100 square kilometers.

batholith

What type of volcano forms from alternating layers of tephra and non explosive lava?

composite volcano

What is the name of Alfred Wegener's hypothesis about moving land masses?

continental drift

what are most earthquakes associated with

plate boundaries

The tremendous amount of heat within the Earth powers ___________________

plate tectonics

_______________ push and pull rocks in the same direction along which the waves are traveling.

primary waves

Which type of fault results in horizontal shortening?

reverse

When a divergent plate boundary forms on a continent, (land), a ___________________forms

rift valley

Harry Hess's theory of _________________________ explained how ocean crust is generated and destroyed.

seafloor spreading

look at figure for subduction zone

section C

What is the study of earthquakes called?

seismology

what is the study of earthquakes called

seismology

How is a volcanic crater connected to a magma chamber?

by a vent

Fractures in rock where sections of rock might suddenly move to create and earthquake are called _________________

faults

What evidence did Wegener use to estimate the time of the continent Pangaea's break up into smaller continents?

fossil data

When magma reaches the surface it is called___________________

lava

What causes the seafloor to spread?

rising molten magma

A wide, dome shaped volcano built from thin, freely flowing lava is called a(n) __________ ________

shield volcano

Hawaii, which sits over a HOT SPOT located near the center of the Pacific Plate, is which type of volcano?

shield volcano

What is the rating from the Richter Scale based on?

size of the largest wave

How many times larger is a magnitude 3 than a magnitude 1 earthquake on the Richter Scale?

100 times

A ___________________ is a device that can detect changes in the strength of the Earth's magnetic field.

Magnetometer

Which type of wave arrives first at a seismic facility?

P

Places where two tectonic plates are moving away from each other are called _____________________________.

divergent boundaries

What is the Earth's core composed of?

iron and nickel

Why does magma move up and through the Earth's crust?

it is less dense than the surrounding rock

During the time of Pangaea, what had the greatest impact on Earth's climate?

it was a time of a giant global ocean

Which mineral may preserve magnetic patterns on the ocean floor, in support of tectonic plates?

magnetite

What two topographic features of the ocean floor were discovered only with the use of sonar?

mid ocean ridges and deep sea trenches

Which scale measures the damage done by an earthquake to determine an earthquake's intensity?

modified mercalli scale

Most of the world's major earthquakes occur in the areas bordering the _________________________

pacific ocean

What is the study of the Earth's ancient magnetic record?

paleomagnetism

The supercontinent from Wegener's theory of continental drift is called ___________________________.

pangea

___________________ is the force per unit area acting on a material.

stress

What type of fault is the San Andreas Fault

strike slip

Which waves are called body waves?

surface waves only

Which type of stress pulls a material apart?

tension

Rock fragments thrown into the air during a volcanic eruption are called _______________

tephra

Much of the Earth's internal heat comes from _______________________

the decay of radioactive materials

What are shallow, intermediate, and deep earthquake classifications based on?

the depth of the focus

Why does knowledge of Earth's interior come from seismic waves?

they change speed and direction when they encounter different materials

A place where two plates slide laterally past each other is called a _______________________________

transform boundary

When does magma form?

when temperatures are hot enough to melt rock

Rocks close to the mid-ocean ridge are _____________________ rocks far from the mid-ocean ridge

younger than

the subduction of an oceanic plate beneath a continental plate produces a

a chain of volcanic mountains

What happens as a lithospheric plate moves over a HOT SPOT?

a chain of volcanoes form

____________________ is the internal resistance to flow of a liquid.

viscosity

What are large, angular fragments thrown from a volcano called?

volcanic blocks