Geology of the National Parks

Welcome to Unit 2


Plate Tectonics I: Making Mountains and Earthquakes

Road sign: “Caution fault zone, watch for cracks in road” on the Big Island of Hawaii
Road sign about cracks on road in a fault zone
Credit: USGS
“If they’d lower the taxes and get rid of the smog and clean up the traffic mess, I really believe I’d settle here until the next earthquake.”
— Groucho Marx, about Los Angeles, California
“We learn geology the morning after the earthquake.”
—Ralph Waldo Emerson
“It’s snowing still,” said Eeyore gloomily. “So it is.” “And freezing.” “Is it?” “Yes,” said Eeyore. “However,” he said, brightening up a little, “we haven’t had an earthquake lately.”
—A.A. Milne, The House at Pooh Corner

As you may recall in the beloved Christmas special about Rudolph, at a key point in the story, Yukon Cornelius hacks off a chunk of sea ice—frozen ocean water—so that he, Rudolph, and Hermey the dentist elf can drift away over the ocean and escape from the Abominable Snowman. If you've ever neglected to check the spaghetti sauce you were heating on the stove while watching Rudolph because you were just dying to know whether 'Bumbles bounce', you may have noticed that the stiff scum that forms on top can break into chunks and drift around on the liquid beneath—much like Yukon C's ice block.

In this unit, and the next two, we'll explore the equivalent activity in the Earth, with the hard-frozen upper layer breaking into drifting chunks, melted lava leaking up in cracks to feed volcanoes (vaguely like the water in the crack that the Bumble fell into when trying to catch the heroes), collisions causing earthquakes when blocks run together ("Land, Ho"), and more. Hold onto your teeth, and let's get started for the land of misfit plate boundaries.

Learning Objectives

  • Explain the characteristics of the three major plate boundary types: pull-apart, push together, and slide-past faults and the role each plays in the formation of landforms, the ocean floor, and the spreading of the West.
  • Differentiate between radiation, conduction, and convection and their roles in mountain making and earthquakes.
  • Explain the relationship between Death Valley and the Gulf of California.
  • Demonstrate an understanding of Elastic Rebound Theory
  • Describe plate tectonics.
  • Differentiate between P and S seismic waves and their behaviors.
  • Demonstrate an understanding of the Richter scale and earthquake intensity.
  • Differentiate between the layers of the Earth (lithosphere, mantle, outer core, inner core) and their characteristics.
  • Recognize the factors and pitfalls that go into the prediction of earthquakes.

What to do for Unit 2?

You will have one week to complete Unit 2. See the course calendar for specific due dates.

As you work your way through the online materials for Unit 2, you will encounter a video lecture, several vTrips, some animated diagrams (called GeoMations and GeoClips), additional reading assignments, a practice quiz, a "RockOn" quiz, and a "StudentsSpeak" Survey. The chart below provides an overview of the requirements for this unit.

Overview of Unit 2 Requirements

Read/view all of the instructional materials

No, but you will be tested on all the materials.
Continue working on Exercise #1: Scientific Literature Yes, this is the first of 6 Exercises and is worth 5% of your total grade.
Take the Unit 2 "RockOn" quiz Yes, this is the second of 12 end-of-unit RockOn quizzes and is worth 4.5% of your total grade.
Complete the "StudentsSpeak #3" survey Yes, this is the third of 12 weekly surveys and is worth 1% of your total grade.


If you have any questions, please feel free to email "All Teachers" and "All Teaching Assistants through Canvas conversations.

Keep Reading!

On the following pages, you will find all of the information you need to successfully complete Unit 2, including the online textbook, a video lecture, several vTrips and animations, and two overview presentations.

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Students who register for this Penn State course gain access to assignment and instructor feedback, and earn academic credit. Information about registering for this course is available from the Office of the University Registrar.