Earthquake Review
What is one similarity between P and S waves They both travel through solids They both start at a focus Both begin at the same time Both can be felt at Earth’s surface
Answers will vary
What is another similarity between P and S waves?
Answers will vary
What does a wave’s speed depend on?
The density of a medium What kind of medium it is traveling through
What is a fault?
A break or crack in the Earth’s crust
What is refraction?
The bending of a wave as it travels through a boundary
Do earthquakes always cause destruction?
Nope
How many earthquakes occur each year felt by humans?
Thousands
How many earthquakes occur each year only felt by seismographs?
Millions
Draw a picture of a reverse fault.
What is one difference between P and S waves? P waves travel through liquids and S waves do not P waves are a push and pull motion while S waves are a side to side motion P waves travel faster than S waves P waves will reach a seismograph before S waves S waves cause more destruction than P waves
Answers will vary
What is another difference between P and S waves?
Answers will vary
What is the difference between the epicenter and focus?
Focus – point inside the Earth where an earthquake begins Epicenter – point on Earth’s surface above focus
What is a seismograph?
An instrument that records vibrations in the ground and determines the location and strength of an earthquake
Do earthquakes release energy?
Yep
What causes earthquakes to occur?
Tectonic plates move past each other causing stress (The movement of tectonic plates)
What are the waves of energy that travel through the Earth called?
Seismic Waves
Draw a picture of a normal fault.
What are the 2 scales used to measure earthquake strength?
Richter Magnitude Scale Mercalli Intensity Scale
Where do most earthquakes occur?
At or near plate boundaries
Draw a picture of a strike-slip fault.
What is the difference between the Mercalli and Richter scales?
Mercalli Scale measures the strength of shaking and how much damage was caused to a city Richter Magnitude Scale measures the amount of energy released and what shows up on a seismogram
If you know the distance from the epicenter of an earthquake to 3 seismic stations how could you find where the earthquake originated?
Draw a circle around each city with the radius being the distance away from the epicenter the city is. Once all three circles are drawn where they overlap is where the earthquake originated.
Where in the united states experiences the most earthquakes and why?
California because it is on a fault (plate boundary)
If you had the intensity level of different cities how could you tell where an earthquake started?
It started where the highest intensity levels are
In what direction(s) do earthquakes release waves?
All directions
What is the connection between earthquake strength and occurrence?
Weaker earthquakes occur more often than stronger earthquakes
What is a seismogram?
A tracing of earthquake motion that is created by a seismograph
What kind of deformation leads to earthquakes occurring?
Elastic Deformation
Why does Ohio not experience many earthquakes?
We are not on a plate boundary (or fault)
What is the S-P time interval of the following printout?
49 Seconds