plate boundaries

GOOD MORNING GEOPHYSICISTS!

• KNOW THY BOUNDARIES!

05/02/2023FTWIGANJR.

PLATE BOUNDARIES


EARTHQUAKES EPICENTER

PLATE BOUNDARIE

S

ACTIVITYConverging Continental Plate and Oceanic Plate


What type of plate is Plate A? What about Plate B? Why did you say so?

ANSWER: Plate A is an oceanic plate because it is relatively thinner compared to Plate B. While Plate B is a continental plate because it is thicker and floats higher than the other plate.

Describe what happens to Plate A as it collides with Plate B?

ANSWER: Plate A bends downward because Plate A is denser than Plate B.


What do you think will happen to the leading edge of Plate A as it continues to move downward? Why?

ANSWER: The leading edge of Plate A will start to melt because the temperature beneath the crust (mantle) is higher.

What do you call the molten material?

ANSWER: This molten material is called magma.


What is formed on top of Plate B?

ANSWER: Volcanoes are formed on top of Plate B.

As the plates continue to grind against each other , what other geologic event could take place?

ANSWER: Earthquake could take place as the plates continue to grind each other.


THREE BASIC TYPES OF PLATE BOUNDARIES

USGS Graphics

1. CONVERGENT BOUNDARY is where plates collide and one subducts beneath the other is characterized by volcanic activities and earthquake

● Subduction - a process by which one lithospheric plate descends beneath another

EFFECTS OF PLATE COLLISION

1. Continental Arc Trench System

-develops where oceanic plate subducts beneath a plate with continental crust at its leading edge. - Andesitic- e.g. Peru-Chile Trench


Trench- 05/02/2023FTWIGANJR.

ACTIVITYConvergence of Two Oceanic Plates


Q21. What are the geologic processes/events that will occur because of this plate movement?

ANSWER: Subduction Earthquakes Trenches Volcanoes.

Q22. What geologic features might form at the surface of Plate A?

ANSWER: Volcanoes might form at the surface of Plate A.


Q23. If the edge of Plate A suddenly flicks upward, a large amount of water may be displaced. What could be formed at the surface of the ocean?

ANSWER: Tsunami or Tidal wave


EFFECTS OF PLATE COLLISION

2. Island Arc Trench System

-develops where oceanic plate subducts beneath a plate with oceanic crust at its leading edge and a continent trailing some distance behind- basaltic


How was the Philippine Archipelago

formed?


ACTIVITY Convergence of Two

Continental Plates


Q24. What happened to the strips of clay as they were pushed from opposite ends?

ANSWER: The strips of clay buckled upward.

Q25. If the strips of clay represent the Earth’s Lithosphere, what do you think is formed in the lithosphere?

ANSWER: Mountains are formed in the lithosphere.


Q26. What other geologic event could take place with this type of plate movement aside from your answer in Q25?

ANSWER: Earthquake will occur due to the collision of two plates

Q27. In terms of consequences on the Earths lithosphere, how will you differentiate this type of convergent plate boundary with the other two?

ANSWER: Mountains are formed instead of volcanoes because there is no subduction


EFFECTS OF PLATE COLLISION3. Continental Mountain System

-develops where two continental plates collide, the surface expression will be a mountain range composed of the folded sedimentary rocks derived from sediments deposited in the sea that previously separated the continental blocks.

● Obduction - a process in which one lithospheric plate stays at the same leveland another plate overrides it

ACTIVITY Going Separate Ways


Q28. What are common in the four pictures?

ANSWER: All four pictures show a fissure or a crack between two land masses

Q29. What do you think is happening to the Earth’s crust in those pictures?

ANSWER: The land masses are moving away from each other


Q30. If this event continues for millions of years, what do you think will be the effect on the crust?

ANSWER: The distance between the land masses will be far greater than that what is shown in the picture.

Q31. Complete the drawing below to illustrate your answer in question number 30.

ANSWER:


USGS Graphics

2. DIVERGENT BOUNDARY is where plates move apart at the midocean ridges and create

new lithosphere/new crust by magma pushing up from the mantle

forms submarine mountain range or midoceanic ridge where fissure eruptions of basaltic volcanoes, shallow

earthquake activity, creation of ocean floor, and widening of ocean basin occur.

MID-ATLANTIC RIDGE

RED SEA / E. AFRICAN RIFT


CONTINENTAL DIVERGENT BOUNDARY: BAJA CALIFORNIA


ACTIVITYSlide and Shake



USGS Graphics

3. TRANSFORM FAULT BOUNDARY is where plates move or slide past one another.

is also called conservative boundary.~ faults neither create nor destroy lithosphere

Choose one plate boundary and make

another model that shows all its

features.

Performance Task: Per group or Per individual

HAWAIIAN ISLANDS

What give rise to HAWAIIAN ISLANDS?

ACTIVITYDrop it Like It’s “Hot Spot”


Q36. What can you see on the surface of the bond paper?

ANSWER: The surface of the paper, which is directly in contact with the test tube became wet.

Q37. Let’s say that the paper represents the Earth’s crust; what do you think is represented by the water in the test tube?

ANSWER: Magma from the mantle is represented by the water in the test tube


Q38. What geologic features do you think will be formed at the surfaceof the crust?

ANSWER: Volcanoes will be formed.

Q39. Which of the features, at the surface of the crust, will be the oldest? the youngest? Label these on your paper.

ANSWER: The oldest volcano will be the first one that developed while the youngest volcano is the last one that was formed


Q40. Which of the features will be the most active? The least active? Label these on your paper.

ANSWER: The most active volcano is the youngest one (the one that is currently on top of the magma source). While the least acive volcano is the oldest (because it is already cut-off from the source of magma)


HOT SPOT- known as a magma

chamber, it is located in the mantle.

- Is an area in the mantle from which hot materials rise as a thermal plume.

The Hotspot then explodes, creating a volcano.

The plate then moves. Notice the volcano moves with the plate, but the hotspot stays were it was.

The Hotspot then explodes again, forming a new volcano.

The plate moves again, starting the process over.

Another volcano is then created forming a Volcanic Chain.

Ocean


HOTSPOT: HAWAII

ACTIVITYFind the Center

Bring the following:drawing compassruler


Q1: Where is the epicenter of this hypothetical earthquake?

ANSWER: Cebu City

Q2. What difficulty will you encounter if you only have data from two recording stations?

ANSWER: Assuming that the two circles will intersect, the circles will intersect at two points. Therefore, there will be two locations that could possibly be the epicenter.


Q3. What is the distance of the epicenter from the seismic station?

ANSWER: 9000km

Q4. What do you think is the importance of determining the epicenter of an earthquake?

ANSWER: Locating earthquake epicenters will pinpoint which fault lines are active. Usually, the less active fault line stores great amount of potential energy that could cause major earthquake once released. Therefore, places near fault lines that remain inactive for a long period of time are due to experience a major earthquake.


HOW TO LOCATE THE EPICENTER OF AN

EARTHQUAKE?


TRIANGULATION METHOD

~ is used to determine the exact location of the epicenter. ~ a method that involves taking seismographic

measurements from at least three separate seismic stations.


PHILIPPINE MONITORING STATIONS

END OF THE LESSON


plate boundaries

Education