UNIT 6; “WATER & CLIMATE”



NOTE PACKET # 12

“PLATE TECTONICS”

NAME; EARTH SCIENCE

PERIOD;

PLATE TECTONICS

Plate Tectonic Theory states that…

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➢

➢

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1 – On which plate is New York State located?

2 – What is the name of the feature that runs down the center of the

Atlantic Ocean?

3 – What two features are located on the Western edge of North

America?

EVIDENCE FOR PLATE TECTONICS

1 –

2 –

3 –

4 –

5 –

6 –

1) Shape of the continents

➢

Example; and

2) Matching features on separated continents.

*

*

*

*

3) Zones of Crustal Activity.

*

*

*

4) Age of the Seafloor

*

*

*

5) Paleomagnetism

*

*

*

[pic]

6) Heat flow and Seafloor Elevation

Heat flow -

* Heat flow is high

( ).

* Elevation of the seafloor is

* As the rocks cool they

1) The diagram below represents the pattern of normal and reversed magnetic polarity and the relative age of the igneous bedrock composing the ocean floor on the east side of the Mid-Atlantic Ridge. The magnetic polarity of the bedrock on the west side of the ridge has been deliberately left blank.

Which diagram best shows the magnetic pattern and relative age of the igneous bedrock on the west side of the ridge?

[pic][pic][pic][pic]

2) Which observation about the Mid-Atlantic Ridge region provides the best evidence that the seafloor has been spreading for millions of years?

(1) The bedrock of the ridge and nearby seafloor is igneous rock.

(2) The ridge is the location of irregular volcanic eruptions.

(3) Several faults cut across the ridge and nearby seafloor.

(4) Seafloor bedrock is younger near the ridge and older farther away.

3) Explain why most major earthquakes are found in specific zones instead of being randomly scattered across Earth’s surface.

4) Which coastal area is most likely to experience a severe earthquake?

(1) east coast of North America

(2) east coast of Australia

(3) west coast of Africa

(4) west coast of South America

Base your answers to questions 5 through 6 on the map below. The map shows the continents of Africa and South America, the ocean between them, and the ocean ridge and transform faults. Locations A and D are on the continents. Locations B and C are on the ocean floor.

5) The hottest crustal temperature measurements would most likely be found at location

(1) A (3) C

(2) B (4) D

6) Which graph best shows the relative age of the ocean-floor bedrock from location B to location C?

[pic] [pic] [pic] [pic]

PLATE BOUNDARIES

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Earth Science Reference Tables; TECTONIC PLATES (ESRT page 5)

1) Name the three types of plate boundaries that are given on the diagram.

1 -

2 -

3 -

2) List four of the Major plates.

1 - 3 -

2 - 4 -

3) List two Hot Spots that are given on the diagram.

1 - 2 -

4) For each of the plates listed below, list the name and type of plate boundary that separates those plates.

name type

North America & Eurasian

Indian-Australian & Pacific

South American & Nazca

South American & African

Indian-Australian & Eurasian ----------none--------

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Three Types of Plate Boundaries

1)

2)

3)

1) Divergent

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➢

➢

➢

➢

2) Convergent

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There are three types;

1.

2.

3.

subduction zone

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➢

➢

ocean trench

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➢

➢

island arc

➢ (ex )

➢ produced from

volcanic arc (mountains)

➢

(Example; )

➢

Orogeny

➢

➢

➢

Ex)

Three types of Convergent boundaries

1 -

Example;

Label the following;

lithosphere (twice)

oceanic crust

continental crust

trench

subduction zone

island arc

partial melting

2 -

Example;

Label the following;

asthensophere (twice)

lithosphere (twice)

oceanic crust

continental crust

trench

subduction zone

mountain belt

partial melting

3 -

Example;

Label the following;

continental crust (twice)

lithosphere (twice)

asthenosphere

folded mountains

3) Transform Plate Boundaries

Ex)

Driving force for Plate Tectonics

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draw diagram

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➢

Hot Spots

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1) The edges of most lithospheric plates are characterized by

(1) reversed magnetic orientation

(2) unusually rapid radioactive decay

(3) frequent volcanic activity

(4) low P-wave and high S-wave velocity

2) The map below shows the northern section of the boundary between the Arabian Plate and the African Plate. Arrows show the relative direction of plate motion.

Which type of plate boundary is located at the Jordan Fault?

(1) divergent (3) convergent

(2) subduction (4) transform

3) Why does the oceanic crust sink beneath the continental crust at a subduction boundary?

(1) The oceanic crust has a greater density.

(2) The oceanic crust is pulled downward by Earth’s magnetic field.

(3) The continental crust has a more mafic composition.

(4) The continental crust is pulled upward by the Moon’s gravity.

4) The diagram below shows the interaction of two tectonic plates.

The type of plate boundary represented in the diagram most likely exists between the

(1) Antarctic Plate and the African Plate

(2) Antarctic Plate and the Indian-Australian Plate

(3) South American Plate and the Nazca Plate

(4) South American Plate and the African Plate

5) The movement of tectonic plates is inferred by many scientists to be driven by

(1) tidal motions in the hydrosphere

(2) density differences in the troposphere

(3) convection currents in the asthenosphere

(4) solidification in the lithosphere

6) Which two tectonic plates are separated by a mid-ocean ridge?

(1) Indian-Australian and Eurasian

(2) Indian-Australian and Pacific

(3) North American and South American

(4) North American and Eurasian

7) The diagram below shows a tectonic plate boundary.

Which mantle hot spot is at a plate boundary like the one shown in this diagram?

(1) Hawaii Hot Spot

(2) Yellowstone Hot Spot

(3) Galapagos Hot Spot

(4) Canary Hot Spot

8) The diagram below shows some features of Earth’s crust and upper mantle.

[pic]

Which model most accurately shows the movements (arrows) associated with the surface features shown in the diagram?

[pic] [pic] [pic] [pic]

EARTH’S DYNAMIC CRUST AND INTERIOR

Small Scale Crustal Changes

original horizontality

*

*

deformed strata

*

Types of deformed strata…..

1)

2)

3)

4)

folded strata

*

draw diagram

tilted strata

*

draw diagram

faulted strata

fault –

draw diagram

Uplift

*

Evidence;

Locating an Epicenter.

Earthquakes occur in many distance places, and many of them occur under oceans. However, a seismologist with suitable equipment does not have to be near one to determine its location, depth, and magnitude. The violent movement within the earth that we call earthquakes dissipate some of their energy in the form of waves (called seismic waves) radiated in every direction form the points within the earth where the rock material has actually moved. Such a point of movement is called the focus of an earthquake. Sensitive instruments called seismometer detect these waves, and other instruments, called seismographs, record the time of arrival and the intensity of these wave patterns. With three such records (called seismograms), a seismologist can rather easily locate the epicenter, the point on the earth's surface directly above the focus of the earthquake, and determine the magnitude of the earthquake.

seismic waves - the energy waves given off by an earthquake.

focus - the place where an earthquake originates.

seismometers - instruments that detect seismic waves.

seismographs - an instrument used to detect and record seismic waves.

epicenter - the point on the earth's surface directly above the focus of the earthquake.

How many seismograms are needed to determine the epicenter of an earthquake?

Travel time

Turn to page 11 of your Earth Science Reference Tables and find "Earthquake P-wave and S-wave Travel Time" diagram.

1) How long does it take a P wave to travel 2000 km?

2) How long does it take a S-wave to travel 2000 km?

3) Which wave is faster?

4) Which wave will reach a seismic station first?

5) How long does it take a P-wave to travel 8000 km?

6) How long does it take a S-wave to travel 8000 km?

Difference in Travel Time

7) For an earthquake that is 2000 km away, calculate the difference in travel time between the P-wave and S-wave. Show your work.

8) For an earthquake that is 8000 km away, calculate the difference in travel time between the P-wave and S-wave. Show your work.

9) As the distance between the earthquake epicenter and the seismic station increases, what happens to the time difference between the arrival of the P-wave and S-wave?

If you know the difference between the arrival time of the p-wave and the arrival time of the s-wave, you can use the graph to determine the distance to the epicenter.

Distance to the Epicenter

1) Calculate the difference between the arrival time of the p-wave and the arrival time of the s-wave.

2) Take a piece of paper and place the edge next to the travel-time scale on the graph (ESRT p.11; P-wave, S-wave chart).

3) Mark off a distance on the edge of the paper that represents the difference in travel time between the p-wave and s-wave.

4) Move the edge of the paper with the time marks on it across the graph until the upper mark is on the S-wave curve, and the lower mark is on the P-wave curve. (BE certain to keep the paper's edge parallel to the vertical distance lines.)

5) When you have found where the time marks on the paper are exactly on the P and S wave curves, read the distance scale that corresponds to this difference in arrival time.

Example;

1) Calculate the difference between the p-wave and s-wave arrival

times.

2) Use the ESRT to determine the distance to the epicenter.

|STATION |P ARRIVAL TIME |S ARRIVAL TIME |S-P |DISTANCE |

|A |14:05:25 |14:08:00 | | |

|B |14:13:15 |14:22:20 | | |

|C |14:08:15 |14:13:05 | | |

Show your work…….

Complete the first four columns on Data Table A and Data Table B.

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Earthquakes and Igneous Activity, Including Volcanoes.

Earthquake –

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➢ (or )

Four causes for Earthquakes;

1)

2)

3)

4) ***

The cause for most of the major earthquakes is….

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Epicenter vs. Focus of an earthquake.

focus-

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epicenter –

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diagram;

Seismic (earthquake) waves.

A seismograph is

A seismogram is

We will examine two types of seismic waves.

1) - also known as…..

➢ or

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Characteristics;

Movement;

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Types of Materials;

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Velocity;

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(the )

2) - also known as...

➢

➢

Characteristics;

Movement;

➢

( )

Types of Materials;

➢

Velocity;

➢

( )

Velocity of seismic waves

Location of an Epicenter

Earthquake Review

Epicenter vs. Focus

1) The point inside the earth where the first movement occurs is the

2) The location on the Earth's surface is the

P & S Waves

Also known as…

Group these words together according to the wave type.

➢ Compressional

➢ S-Wave

➢ Primary

➢ Secondary

➢ P-Wave

➢ shear

P-wave or S-wave.

1) Compresses rock

2) Slower moving wave

3) Only travels through solids

4) Travels at a greater velocity

5) Displacement is at right angles to the movement of the wave

6) Travels through solids, liquids, and gases

Origin Time of Earthquakes.

➢

– =

Example;

If the s-wave first arrived at a station at 10 hr:12 min: 30 sec and the

seismograph is 5500 kilometers away, when did the earthquake occur?

Magnitude of Earthquakes

magnitude scale

*

* lowest value is less than .

* highest value ~ (rocks break above this number)

Earthquake Hazard

*

*

Emergency Planning

“Drop, Cover, and Hold.

*

*

*

Do not …

most earthquakes only last 10-30 seconds.

Planning…. building codes / techniques.

Tsunami

Japanese meaning – “a harbor wave”

*

• caused by an , , or landslide.

MODEL OF EARTH’S INTERIOR

Seismic waves give us

* layers, composition, density, etc.

* see Earth Science Reference Tables.

INFERRED PROPERTIES OF EARTH’S INTERIOR (ESRT page 10)

1) List the layers of the Earth, from the surface down through the interior.

1)

________________

2)

3)

4)

5)

6)

2) Name the two types of crustal material.

1 - 2 -

3) How do the two types of crustal material compare in density & composition?

4) Which layer of the Earth’s interior has the greatest density?

5) Which layer of the Earth’s interior has the lowest density?

6) What is the pressure at 2200 km depth?

7) Which layer of the Earth’s interior has the greatest pressure?

8) What is the temperature at a depth of 3000 km?

9) Which layer of the Earth’s interior has the greatest temperature?

Zones of Earth

lithosphere

*

crust

*

There are two types of crust;

1)

2)

continental crust

*

* ( )

* (like ).

*

oceanic crust

*

*

* (like ).

*

Moho

*

Mantle

*

*

It is divided into three parts

1)

2)

3)

asthenosphere

*

*

*

*

Core

*

*

(evidence; , )

The core is divided into two parts

1)

2)

Shadow Zone (very impt to understand!)

*

* ~

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7.

8.

7.

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