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CRCT QuestionPrimary seismic waves
a. Are slower than secondaryb. Are the result of shearing
forcesc. Can travel through solids,
liquids and gasesd. Causes Earth’s to roll up and
down*Please have Tier 1 Out
When is tier 2 Earthquakes due?
When is the vocabulary sheet due?
Part 1: Deformation
http://www.youtube.com/watch?v=DppbibMhAXU
Flashcards
Quiz the person sitting next to you,
then switch!!!
Focus vs. Epicenter
Focus is in the point beneath the earth surface where the
rock breaks. Epicenter is above it.
The Epicenter is
the point beneath the earth where
the rock breaks. The
focus is above it.
Organizing! Organize the following phrases into the three major types of stress!
Shearing, Tension, and shearing
Squeezes the rocks of the crust Pushes in opposite direction Pulls the rocks Decreases volume Increases volume Increases density Decreases density Tear and twist
Candy Toss
Question
When plates slide past one another this is what type of boundary?
Answers
Transform
Question
When plates collide this is what type of boundary?
Answers
Convergent
Question
What happens to a rock if it’s undergoing shearing?
Answers
Bends and breaks
Question
What is it called when that Earth BENDS?
Answers
Folding
Question
Squeezing an object describes what kind of stress?
Answers
Compression
Question
Before Lava hits it is called:
Answers
Magma
Question
A volcanic belt that circles the Pacific Ocean is called:
Answers
Ring of Fire
Coffee Talk
All you need to know aboutEarthquakes
Today: seismic waves
II. Seismic Waves-Also known as Earthquake Waves
Seismic Metaphor
Seismic waves ripple like when you throw a stone into a lake or pond
Snap Your Fingers and observe what is happening.
When you snap your fingers, imagine that each finger is a big chunk of rock deep inside the earth's surface. Like your fingers, one rock mass is forced
against another.
Extra: Seismic WavesDeep inside the earth, rocks are constantly
being pressured to move until the strain is so great
the rocks can no longer bear the tension.
Suddenly, there is a movement that releases all the energy--some of which has been building
up for years. This released energy travels
through rocks in the form of vibrations called
seismic waves.
Blue primary waves followed by red secondary waves move outwardin concentric circles from the epicenter of an earthquake off British Columbia and Washington State.
Three Seismic Waves
The energy of all three types of waves is passed from one rock particle to another in the same way one domino hits another and then another in a line of falling dominoes.
These seismic waves cause back-and-forth, side-to-side, and up-and-down motions in the earth. These motions are what people sense during a earthquake.
a. Primary Waves
▪Fastest waves▪P waves▪Moves through solids, liquids, and gases▪Speeds up in denser material▪Push and pull waves
What it Looks like!
Primary waves travel the fastest. P-waves are the first waves to reach the Earth's surface after an earthquake.
b. Secondary Waves
▪S waves▪Slower than P waves▪Travels through solids but not liquids and gases▪Speeds up in denser material▪Movement is side to side
What it Looks Like!
Modeling P and S Waves
I need 10 volunteers! S waves: do "the wave" as they
would in a football stadium, raising their arms and lowering them as the next person raises his or hers.
P Waves: gently grip each other's shoulders and having one pull or push the next person in line.
C. Surface Waves
▪L waves (*think Land)▪Slowest waves▪Originates at the epicenter▪Creates the wave movements on the Earth’s surface▪Causes the most damage
Let’s watch it!
Review #1
Match the following into three separate categories: P, S, L waves
Slowest Fastest Primary Surface Secondary Causes the most damage Travels through solids, liquids, and
gases
Measuring Seismic Waves
III. Seismograph – a. is an instrument that detects
and measures seismic b. Waves *typo in spacing!c. Seismologist – scientists who
study earthquakes, can determine the strength of them
Seismograph
This is an image of a seismograph, an instrument used to record the energy released by an earthquake. When the needle is moved by the motion of the earth, it leaves a wavy line.
When you look at a seismogram, there will be wiggly lines all across it. These are all the seismic waves
that the seismograph has recorded.
Seismogram
The Surface waves are the other, larger waves markedon this seismogram. Surface waves travel slower than
S waves (which are slower than P waves) so they arrive at the seismograph after the S waves.
Surface Waves Arrive Last
Add to Notes
I. Measuring Earthquakes
There are at least 20 different types of measures
3 of them are the Mercalli scale, Richter scale, and the Moment Magnitude scale
Magnitude is a measurement of earthquake strength based on seismic waves and movement along faults
a. The Mercalli Scalerate earthquakes according to their intensity
The intensity of an earthquake is the strength of ground motion in a given place
Is not a precise measurement
But, the 12 steps explain the damage given to people, land surface, and buildings • The Mercalli scale uses Roman
numerals to rank earthquakes by how much damage they cause
B. The Richter Scaleis a rating of the size of seismic waves as measured by a particular type of mechanical seismograph
All over the world, geologists used this for about 50 years
Electric seismographs eventually replaced the mechanical ones used in this scale
Provides accurate measurements for small, nearby earthquakes
Does not work for big, far ones
Locating the Epicenter Since the P waves
travel faster than the S waves, scientists can use the difference in arrival times to see how far away the earthquake occurred.
It does not tell the direction however.
Determining Direction One station can
only learn how far away the quake occurred.
They would draw a circle at that radius.
If three stations combine their data, the quake occurred where the three circles overlap.
How Earthquakes Cause Damage
The severe shaking provided by seismic waves can damage or destroy buildings and bridges, topple utility poles, and damage gas and water mains With their side to side, up and down movement, S waves can damage or destroy buildings, bridges, and fracture gas mains.
Review #2
What is the measurement of an
earthquakes strength?
Tier 2 Options
Option 1: Create a radio announcement for an earthquake warning
Option 2: Letter to the editor
Brainstorm
Help give yourself an outline
Make sure you have incorporated the vocabulary
Tier 2 Earthquakes Rubric
Part 1: Vocabulary (9 points each) Did you accurately communicate the following vocabulary
1. Focus2. Epicenter3. Stress (Tension, shearing, compression)4. Seismic waves (P waves, s waves, surface waves)5. Plate Boundaries6. Faulting7. Folding8. Seismograph9. Richter Scale 10. Plate tectonics
Part 2: Presentation (10 points) Is your project neat, legible, creative, and organized