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Name:
Date:
Subject:
Earthquakes
Objectives
Objective 1: ASWBAT describe how earthquakes happen and where earthquakes usually
occur.
Objective 2: ASWBAT describe what the focus and epicenter of an earthquake is.
Objective 3: ASWBAT identify and describe two types of seismic waves.
On a scale of 1 – 3 how well you can do on this objective now.
(1 – Not at all
2 – I know it a little bit
3 – I know it very well)
Highlight your choice.
Objective: 1
Objective: 2
Objective: 3
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Key Vocabulary Words
On a scale of 1 – 3 how well you know the vocabulary words below.
(1 – Not at all 2 – I know it a little bit 3– I know it very well)
Earthquake
Epicenter
P Waves
S Waves
Fault Zones
Focus
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Pre-quiz
Do your best to answer the following questions.
1. What is a plate boundary?
Answer:
2. What are the three types of plate boundaries?
Answer:
3. What is the theory of plate tectonics?
Answer:
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Earthquakes – What causes them?
The Earth’s crust is made of many large pieces called tectonic plates and because of
extreme forces inside the Earth these plates are in constant motion. This motion causes
stress to build up where the plates are grinding along each other, pushing into each other
or pulling away from each other. This stress builds until the plates themselves break.
When they break large amounts of energy is released in the form of waves. This release of
energy from the stress built up in the crust is what we call Earthquakes. Earthquakes are
caused by the release of stress that builds up as the plates move around the Earth.
Earthquakes
Action! – Push the blocks together as hard as you can until they slip past each other.
Video: 1906 Earthquake
1. What causes an earthquake?
Answer:
Earthquakes – Focus and Epicenter
Using sensitive measuring devices scientists are able to tell where an earthquake started
and how deep it was. We call the exact place where the earthquake started the focus. The
depth of the focus of an earthquake can vary from a few miles under the surface to over 50
miles below the surface. The place on the surface that is directly above the focus is called
the epicenter. This is where the earthquake is the strongest and causes the most damage.
Video: 2014 Napa Earthquake: http://fox40.com/2014/08/28/geologists-locateepicenter-of-napa-earthquake/
1. What is the focus of an earthquake?
Answer:
2. What is the epicenter of an earthquake?
Answer:
Earthquakes – Where do they mostly happen?
Earthquakes happen all over the world, but they don’t just happen anywhere. In fact most
of the worlds earthquakes happen near the plate boundaries. This is because of the
different directions that the plates move causes them to rupture and crack. These
boundaries are where the plates grind against, smash into and pull apart from each other.
Some earthquakes do happen in the middle of the plates, but these are much less frequent.
Japanese Earthquake (Convergent Boundary)
Action! – Click on the following link and see where the world’s earthquakes have
happened over the past 30 days.
World Earthquake Map Link: http://earthquaketrack.com/
Video: How Earthquakes Work
Link: http://www.youtube.com/watch?v=-zNyVPsj8zc&feature=related
1. Most of the world’s earthquakes happen near what? Why?
Answer:
Fault Zones
Faults are cracks that exist in the Earth’s crust. Fault zones are where there are many
fault lines in one area. The bay area is a fault zone.
Action! – Click on the following link for information on the faults of the Bay Area.
Bay Area Fault Zone Map Link:
https://www.google.com/maps/d/viewer?oe=UTF8&gl=us&ie=UTF8&msa=0&ptab=2&m
id=zdXAjDB74Urk.kMVL380GIUIg
1. What is a fault?
Answer:
2. What is a fault zone?
Answer:
Earthquakes – Seismic Waves
The energy that is released in an earthquake travels in waves. The waves from an
earthquake are called seismic waves. These waves are what we experience as the shaking
during an earthquake. They are what make earthquakes so dangerous. The shaking from
these waves is what sometimes causes building to fall over. Two basic types of waves are
released in an earthquake. One type of wave is called a primary wave or P – wave. P waves push back and forth in the direction that the wave is traveling. The other type of
wave is called a secondary waves or S – waves. S – waves shake side to side and up and
down in an s motion.
P and S Wave Animation Link:
http://www.classzone.com/books/earth_science/terc/content/visualizations/es1002/es
1002page01.cfm?chapter_no=visualization
Action! – Using a slinky create each type of wave.
1. What do we call the waves that are released during an earthquake?
Answer:
2. What is the difference between an S-wave and a P-wave?
Answer:
Article Link: http://www.npr.org/blogs/thetwo-way/2011/09/20/140636070/u-stests-early-warning-system-for-earthquakes
1. Which waves does the article say are more dangerous?
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2. Do you think the early warning will help? Why or why not?
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Quiz
Directions: Answer the following questions to see if you met the objectives.
1. What is an earthquake?
Answer:
2. Where do most earthquakes happen?
Answer:
3. What is the focus of an earthquake?
Answer:
4. What is the epicenter of an earthquake?
Answer:
5. Identify what type of wave the following diagram represents. How do you know?
Answer:
6. Identify what type of wave the following diagram represents. How do you know?
Answer: