Earthquake & Tectonic Plates 2025

Diverging (plate boundary)

two plates spreading apart (division)

Sliding or Transform (plate boundary)

two plates slide past each other (usually broken by transform faults along mid-ocean ridges)

Converging (plate boundary)

two continental plates colliding with each other

Subduction (plate boundary)

convergent but one plate is plunging below another plate (volcanoes)

P waves - primary (earthquake wave)

back & forth (longitudinal) - fastest - solids & liquids

S waves - secondary (earthquake wave)

side to side (transverse) - slower than P waves - only solids

Surface waves (earthquake waves)

rolling waves, up&down, side&side - slowest - most damage close to epicenter

Crust (layers of the Earth)

outermost thinnest layer, cool & solid rock, oceanic (denser) & continental crust, 50C

Mantle (layers of the Earth)

layer between crust and core, solid plastic hot rock, 2900km, 1250C

Core (layers of the Earth)

center of Earth, most dense, iron & nickel, inner (solid metal), outer (liquid metal), 3500km, 6000-7000C

lithosphere/what its made of (plate tectonic notes)

the crust & uppermost portion of the mantle (rigid mantle)

Plate Tectonic Theory (plate tectonic notes)

The earth is covered by about 20 moving plates

Asthenosphere (plate tectonic notes)

below lithosphere, molten (plastic) & flows, plates driven by convection currents

Earth’s interior is made up of…

four layers; crust, mantle, outer core, & inner core

crust: solid, outer layer of Earth

mantle: part solid, part melted layer beneath the crust

outer core: melted, metallic layer beneath the mantle

inner core: solid, metallic layer beneath the outer core

Rigid mantle (Earth’s interior)

outer-most part of the mantle is completely solid

Oceanic crust (layers of the Earth & Earth’s interior)

more dense, 4-7km thick, made of thin layer of rock basalt

Continental Crust (layers of the Earth & Earth’s interior)

less dense, 20-40km thick, made of thick layer of rock granite

When is material liquid? (Earth’s interior)

when interior temp is higher than melting point (outer core)

Traveling deep down from crust to inner core (Earth’s interior)

1. the materials get increasingly dense

2. the pressure increases

3. the temperature increases

Which 2 layers make up Lithosphere? (Earth’s interior)

Rigid Mantle & crust

Where is the crust thicker, oceanic or continents? (Earth’s interior)

Continental crust

Where is the crust denser, oceans or continents? (Earth’s interior)

Oceanic Crust

What is the outer core believed to be made up of? (Earth’s interior)

Liquid iron & nickel

What is the inner core believed to be made up of? (Earth’s interior)

Iron & nickle

What 2 layers of the Earth are either partially or totally melted? (Earth’s interior)

Asthenosphere & outer core

Between which 2 layers do you find the MOHO? (Earth’s interior)

Between the crust & the mantle

What rock is continental crust made up of? (Earth’s interior)

Granitic rocks

What rock is oceanic crust made up of? (Earth’s interior)

Basaltic rocks

What happens to the temperature as you travel deeper into the Earth? (Earth’s interior)

temperature increases/rises

What happens to pressure as you travel deeper into the Earth? (Earth’s interior)

the pressure increases

Why is Asthenosphere called “plastic mantle”? (Earth’s interior)

its a melted rock not completely into liquid, thick & gooey,

What are the 3 layers of the mantle? (Earth’s interior)

lithosphere, asthenosphere, mantle

Do plates move together or apart at mid ocean ridges? (Earth’s interior)

apart - divergent

Do plates move together or apart at trenches? (Earth’s interior)

together - convergent

Are mountains found at mid ocean ridges or trenches? (Earth’s interior)

trenches (cascades)

Convergent Plate Boundaries Trenches (tectonic plate coloring map)

• trench + overriding plate + subducting plate

1. peru-chile trench: south American plate (overriding) - Nazca plate (subducting)

2. Aleutian trench: north American plate - pacific plate

3. Tonga trench: pacific plate - indian-austrialian plate

4. mariana trench: Philippine plate - pacific plate

Divergent Plate Boundaries Ridges (tectonic plate coloring map)

• ridge + two divering plates

1. mid-atlantic ridge (north of equator): north American plate & Eurasian plate

2. mid-atlantic ridge (south of equator): African plate & south American plate

3. East pacific ridge: pacific plate & antarctic plate

4. Southeast Indian Ridge: antarctic plate & Indian-Australian plate

5. Southwest Indian Ridge: antarctic plate & African plate

6. Mid-Indian Ridge: African plate & Indian-Australian plate

Transform Plate Boundary Fault (tectonic plate coloring map)

• fault + two sliding plates

1. San Andreas Fault: pacific plate & North American plate

Hot Spots - at/far from plate boundary (tectonic plate coloring map)

• AT vs FAR from plate boundary

1. Hawaii - FAR

2. Galapagos - AT

3. Canary Islands - FAR

4. Iceland - AT

5. St. Helena - FAR

6. Bouvet - AT

7. Easter Island - AT

8. Tasman - FAR

9. Yellowstone - FAR

Plate Boundaries by Coordinates (tectonic plate coloring map)

• latitude - longitude - type of plate boundary

  1. 50°S - 30°E - Transform

  2. 40°N - 20°W - Transform

  3. 0° - 30°E - Divergent

  4. 70°N - 140°E - complex

  5. 45°N - 150°E - convergent

What are the 3 types of seismic waves? (Review for Earthquake Quiz)

1. P waves (primary, 1st wave, solids & liquids)

2. S waves (slower than P waves, only solids)

3. Surface waves ( slowest wave, causes all damage)

Which waves are transverse? (Review for Earthquake Quiz)

P waves & surface waves are longitudinal (back & forth)

Which waves tend to do most damage & why? (Review for Earthquake Quiz)

Surfaces waves cause the most damage because they move in both directions & are on the surface

Describe what each wave can & cannot travel through (Review for Earthquake Quiz)

1. P waves travel through solids & liquids

2. S waves travel thought solids

3. Surface waves travel through solids

What are the relative speeds of the waves? - fast, middle slow (Review for Earthquake Quiz)

1. P waves = fastest

2. S waves = middle

3. Surface waves = slowest

What is the difference between the focus of an earthquake and the epicenter? (Review for Earthquake Quiz)

The focus is within the Earth where rocks break. The epicenter is the point above the focus on the Earth’s surface.

What does the Richter scale measure? (Review for Earthquake Quiz)

It measures the magnitude (strength) of the earthquake

What is the difference of one number on the Richter scale equivalent to in terms of relative energy? And a difference of two? (Review for Earthquake Quiz)

Each number on the scale equals a 30x increase in energy

• 4 - 5 - 6

• 4 × 30 = 5

• 5 × 30 = 6

• continues

If you are going to locate the epicenter of an earthquake what is the minimum number of separate seismic stations you? Why? (Review for Earthquake Quiz)

You need 3 stations minimum, so that the 3 arcs can intersect at one point

Given a seismogram with enough seismographs reporting, list the steps you would take to calculate the distance of each station to the epicenter & to locate the epicenter. (Review for Earthquake Quiz)

1. identify arrival time of P & S waves

2. find lag time by subtracting P waves from S waves

3. measure using a compass & repeat for 2 other stations

What do the circles you would draw represent? (Review for Earthquake Quiz)

The circles represent the distance from a seismic station to the epicenter

What is liquefaction? (Review for Earthquake Quiz)

Occurs when wet, sandy soil gives way during an earthquake

What type of ground is under San Lorenzo? (Review for Earthquake Quiz)

Clay with some sand mixed in it; unconsolidated soil

How does focus depth relate to earthquake damage? (Review for Earthquake Quiz)

A deep focus earthquake will transmit less energy to the surface

Describe the theory of plate tectonics (Plate Tectonics Review Sheet)

The lithosphere is made of 7 large pieces called tectonic plates. These plates fit together like puzzle pieces and move in relation to one another. The theory describing the movement of plate is called plate tectonics.

List the details of the evidence for plate tectonics - include magnetic reversal & how often it happens (Plate Tectonics Review Sheet)

Same type of animals lived on ocean continents that are now oceans apart. Ocean floor structures gave evidence for the movement of continents called continental drift. The iron minerals in molten rock cool & align themselves parallel to the Earth’s magnetic field every 300,000 years the magnetic pole reverses itself.

Name & describe the 4 types of plate boundaries, include what structures are formed at each boundary, & one example of each boundary from the plate map. (Plate Tectonics Review Sheet)

1. Convergent Plate Boundary - oceanic plates dive beneath continental or oceanic plates

2. Transform Fault Boundary - rocks move horizontally past each other at faults along plate boundaries

3. Divergent Plate Boundary - two plates move apart creating a gap between them

Make a drawing that shows position of Earth’s crust, mantle, outer core, inner core & describe the composition, temperature,, & percentage of the Earth’s volume each occupies. (Plate Tectonics Review Sheet)

• Mantle is 84% of Earth’s volume

• Inner core is 16% of Earth’s volume

  1. Mantle: rock denser than crust, 1800 miles thick, 2280°

  2. Crust - hard, solid rock, 12-25 miles thick, 347°

  3. Outer Core - liquid metal, >5400°F

  4. Inner Core - solid metal, >10,800°F

What are “convection currents” in terms of the plate tectonics theory? (Plate Tectonics Review Sheet)

The flow of magma up through the mantle pushes the lithospheric plates in the form of convection currents which is a heating/expansion followed by a cooling/contraction.

Make a drawing that illustrates how convection currents are thought to cycle through the Earth’s interior & surface (Plate Tectonics Review Sheet)

N/A - ion got time to upload a photo of it go look at review sheet

Where do most earthquake & volcanoes occur? (Plate Tectonics Review Sheet)

At plate boundaries

Where is the new material being added to the Earth’s crust? (Plate Tectonics Review Sheet)

At divergent plate boundaries

Where is the crust material returning to the mantle? (Plate Tectonics Review Sheet)

At convergent plate boundaries

AT what type of plate boundary do volcanoes most occur & why? (Plate Tectonics Review Sheet)

Volcanoes occur at convergent boundaries when the oceanic plate dives beneath the continental plate

Define asthenosphere & lithosphere (Plate Tectonics Review Sheet)

• Asthenosphere: hot, plastic portion of mantle

• Lithosphere: the crust & rigid upper portion of the mantle

How does oceanic crust differ from continental crust? (Plate Tectonics Review Sheet)

Oceanic crust is more dense than continental crust

The pacific plate contains 3 types of plate boundaries, which & where? (Plate Tectonics Review Sheet)

1. Transform Boundary - North America (San Andreas Fault)

2. Convergent Boundary - South America

3. Divergent Boundary (middle of pacific ocean)

What type of boundary is each of the follow an example of: (Plate Tectonics Review Sheet)

1. Himalayan Mountains - convergent boundary

2. Philippine Islands - subduction boundary

3. East Pacific Rise - divergent boundary

4. San Andreas Fault - transform Fault boundary

What is the epicenter of an earthquake? (google.com)

the point on the Earth's surface directly above the earthquake's focus, also known as the hypocenter, where the earthquake originates underground

What causes tsunamis? (google.com)

caused by large sudden displaces of the ocean by earthquakes on converging tectonic plate boundaries (when earthquake occurs underwater), but also by landslides, volcanic activity, or meteorite impacts