Earthquake ReviewEarthquake Review

What is one similarity between What is one similarity between P and S wavesP and S waves

• Answers will vary

What is another similarity What is another similarity between P and S waves?between P and S waves?

• Answers will vary

What does a wave’s speed What does a wave’s speed depend on?depend on?

• The density of a medium

• What kind of medium it is traveling through

What is a fault?What is a fault?

• A break or crack in the Earth’s crust

What is refraction?What is refraction?

• The bending of a wave as it travels through a boundary

Do earthquakes always cause Do earthquakes always cause destruction?destruction?

• Nope

How many earthquakes occur How many earthquakes occur each year felt by humans?each year felt by humans?

• Thousands

How many earthquakes occur each How many earthquakes occur each year only felt by seismographs?year only felt by seismographs?

• Millions

Draw a picture of a reverse fault.Draw a picture of a reverse fault.

What is one difference between What is one difference between P and S waves?P and S waves?

• Answers will vary

What is another difference What is another difference between P and S waves?between P and S waves?

• Answers will vary

What is the difference between What is the difference between the epicenter and focus?the epicenter and focus?

• Focus – point inside the Earth where an earthquake beginsEpicenter – point on Earth’s surface above focus

What is a seismograph?What is a seismograph?

• An instrument that records vibrations in the ground and determines the location and strength of an earthquake

Do earthquakes release Do earthquakes release energy?energy?

• Yep

What causes earthquakes to What causes earthquakes to occur?occur?

• Tectonic plates move past each other causing stress (The movement of tectonic plates)

What are the waves of energy that What are the waves of energy that travel through the Earth called?travel through the Earth called?

• Seismic Waves

Draw a picture of a normal fault.Draw a picture of a normal fault.

What are the 2 scales used to What are the 2 scales used to measure earthquake strength?measure earthquake strength?

• Richter Magnitude Scale

• Mercalli Intensity Scale

Where do most earthquakes Where do most earthquakes occur?occur?

• At or near plate boundaries

Draw a picture of a strike-slip Draw a picture of a strike-slip fault.fault.

What is the difference between What is the difference between the Mercalli and Richter scales?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 If you know the distance from the epicenter of an earthquake to 3 epicenter of an earthquake to 3

seismic stations how could you find seismic stations how could you find where the earthquake originated?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 Where in the united states experiences the most experiences the most

earthquakes and why?earthquakes and why?

• California because it is on a fault (plate boundary)

If you had the intensity level of If you had the intensity level of different cities how could you tell different cities how could you tell

where an earthquake started?where an earthquake started?

• It started where the highest intensity levels are

In what direction(s) do In what direction(s) do earthquakes release waves?earthquakes release waves?

• All directions

What is the connection between What is the connection between earthquake strength and earthquake strength and

occurrence?occurrence?

• Weaker earthquakes occur more often than stronger earthquakes

What is a seismogram?What is a seismogram?

• A tracing of earthquake motion that is created by a seismograph

What kind of deformation leads What kind of deformation leads to earthquakes occurring?to earthquakes occurring?

• Elastic Deformation

Why does Ohio not experience Why does Ohio not experience many earthquakes?many earthquakes?

• We are not on a plate boundary (or fault)

What is the S-P time interval of the What is the S-P time interval of the following printout?following printout?

• 49 Seconds