Plate Tectonics, Earthquakes, and Volcanoes

Chapter 10 Plate Tectonics

Most Essential Learning Competencies

Describe and relate the distribution of active volcanoes, earthquake epicenters, and major mountain belts to Plate Tectonic Theory

Pre-test

15 items - Multiple Choice

Multiple Choice

What is the outermost layer of the Earth?

• crust

• inner core

• mantle

• outer core

Multiple Choice

The crust and upper mantle make up Earth’s _________.

• asthenosphere

• continents

• core

• lithosphere

Multiple Choice

Which statement about the Earth’s crusts is CORRECT?

• Continental and oceanic crusts have the same weight.

• Continental crust is heavier than oceanic crust.

• Continental crust is thicker than oceanic crust.

• Oceanic crust is thicker than continental crust.

Multiple Choice

What do we call the continuously moving part of the earth’s crust?

• fault

• fissure

• fracture

• plate

Multiple Choice

Which theory states that the entire crust is broken and is continuously moving?

• Continental Drift

• Plate Tectonics

• Seafloor Spreading

• Titanic Theory

Multiple Choice

Which of the following is NOT a result of Plate Tectonics?

• earthquake

• fault lines

• landslides

• mountains

Multiple Choice

This earthquake type happens when the shifting of Earth’s plates is driven by the sudden release of energy within some limited region of the rocks of Earth.

• aftershock

• foreshock

• tectonic

• volcanic

Multiple Choice

How are tsunamis created?

• A submarine earthquake causes huge amount of water to be displaced.

• Differences in temperature cause hot seawater to rise.

• The gravitational pull of the moon causes the ocean water to rise.

• Topography underwater cause disturbances in the oceans’ current.

Multiple Choice

A land mass that projects well above its surroundings is a mountain. What do you call a chain of mountains?

• mountain area

• mountain chain

• mountain range

• mountainous

Multiple Choice

It is the location on the Earth's surface directly above the focus of an earthquake.

• center

• direct center

• epic center

• epicenter

Multiple Choice

If an earthquake begins while you are in a building, the safest thing for you to do is ______.

• call home

• duck near a wall

• get under the strongest table, chair or other piece of furniture

• lie flat on the floor and cover your head with your hands

Multiple Choice

Why is it important to be aware of places prone to earthquakes?

• to identify what crop must be stored

• to identify when to evacuate

• to locate where to stay best

• to perform necessary precautions

Multiple Choice

Which statement BEST describes the location of majority of earthquake epicenters relative to the location of volcanoes around the world?

• They are far adjacent.

• They are always 3 kilometers away from each other.

• They are situated at the same location

• They are not necessarily relevant.

Multiple Choice

How will you relate the distributions of mountain ranges, earthquake epicenters, and volcanoes?

• Mountain ranges are found in places between where volcanoes and earthquake epicenters are also situated.

• Mountain ranges are found in places where volcanoes and/or earthquake epicenters are also situated.

• Mountain ranges are found only in places where earthquake epicenters are situated.

• Mountain ranges are found only in places where volcanoes are situated.

Definition of Terms:

• Triangulation Method-is a method used by seismologists to determine the location of earthquake epicenter using 3 seismic stations

• Earthquake-is the vibration of the Earth due to the rapid release of energy

• Seismology is the study of earthquakes and seismic waves that move through and around the earth

• Seismologist-is a scientist who studies earthquakes and seismic waves and their results, like tsunamis, and landslides

• Focus or known as “hypocenter” is the point within the Earth where an earthquake or an underground explosion originates

• Epicenter -is the point on the earth's surface vertically and directly above the hypocenter (or focus)

• Seismic station -a station for recording oscillations (movements) of the earth’s surface caused by earthquakes and is the primary processing of the records obtained*

• Seismograph or known as seismometer, is an instrument used to detect and record earthquakes

• Seismogram is a visual record that is created by a seismograph

• P-Wave travels faster than other seismic waves and hence is the first signal or wave from an earthquake to arrive at any affected location or at a seismograph that’s why it is also called as primary wave

• S-Wave - is the second wave from an earthquake to arrive at any affected location that’s why it is also known as the secondary wave

• Arrival Time - is the time that a seismic wave (like P and S waves) arrives at a seismic station

• Lag Time - is the difference between arrival times of p and s waves 

Do you agree that Earth’s surface is constantly changing?

• How do these changes occur?

• What do you think are the positive and negative effects of these changes to us?

• How can we prepare, react, and adapt to the upcoming changes?

Structure of the Earth

The crust is the outermost layer of Earth, and it is the one we live on.

What is earth's crust made of?

What is earth's crust made of?

• Continental Crust - thick (10-70km), buoyant (less dense than oceanic crust), mostly old

• Oceanic Crust - thin (~7 km), dense (sinks under continental crust), young

What explains Plate Tectonics?

What explains Plate Tectonics?

What explains Plate Tectonics?

It explains the features and movement of Earth's surface in the present and the past.

What is Plate Tectonics Theory?

What is Plate Tectonics Theory?

• A theory that Earth's outer shell is divided into several plates that glide over the mantle, the rocky inner layer above the core.

• The modern version of continental

  drift, a theory first proposed by scientist Alfred Wegener in 1912. 

If you look at a map of the world, you may notice that some of the continents could fit together like pieces of a puzzle.

What lies beneath the tectonic plates?

What lies beneath the tectonic plates?

•Below the lithosphere (which makes up the tectonic plates) is the Asthenosphere.

How and Why do tectonic Plates move around?

How and Why do tectonic Plates move around?

“Plates” of lithosphere are moved around by the underlying hot mantle convection cells

• In the mantle hot material rises towards the lithosphere 

• The hot material reaches the base of the lithosphere where it cools and sinks back down through the mantle.

• The cool material is replaced by more hot material, and so on forming a large “convection cell” (as pictured in the diagram).

Do you know the location of known volcanoes in Montana or any other states near Montana? Can you locate them in the map? 

​Yellowstone Caldera

A map of Yellowstone National Park, Wyoming, shows the outline of the caldera of the massive Yellowstone supervolcano last erupted about 640,000 years ago.

​Potentially Active Volcanoes in Western United States

• How do structure and composition of the earth cause geologic activities and physical changes?

• What are the possible movements of lithospheric plate movements?

• What proves the movements of the tectonic plates?

What does an earthquake feel like?

What does an earthquake feel like?

The way an earthquake feels depends on where you are, where the earthquake is, and how big the earthquake is

What is an EARTHQUAKE?

EARTHQUAKE

is a vibration of the earth produced by the rapid release of energy most often because of the slippage along a fault in the earth’s crust.

In what form of waves this energy radiates in all directions from the focus?

In what form of waves this energy radiates in all directions from the focus?

SEISMIC WAVES

How are these waves recorded? 

How are these waves recorded? 

  in SEISMOGRAPHS

What Is the Difference Between a Seismogram and a Seismograph?

•    A seismogram is a visual record that is created by a seismograph. 

•    A seismograph is a piece of equipment that records earthquake

  movements. 

What is the scale for earthquakes?

• It was invented in 1935 by Charles F. Richter of the California Institute of Technology as a mathematical device to compare the size of earthquakes. 

• The Richter scale is used to rate the magnitude of an earthquake, that is the amount of energy released during an earthquake.

What are Seismic Waves?

What are Seismic Waves?

The energy that travels through the earth and is recorded on seismographs. 

Primary or P and Secondary or S Waves

• Two types of seismic waves

• are categorized vibrations from an earthquakes

• travel through the earth in different ways and at different speeds

• can be detected and analyzed.

P and S Waves

• * Primary waves arrive at the detector first

• ​ P waves travel through any kind of material,

• Secondary waves arrive at the detector of a seismometer second

• ​S waves only travel through solids.

• Because of the difference in velocity between P and S waves, the distance of earthquake epicenter from the recording station can be determined.

​How do we find the epicenter of an earthquake?

​How do we find the epicenter of an earthquake?

​

Triangulation Method-is a method used by seismologists to determine

the location of earthquake epicenter using 3 seismic stations