++ Earthquake Test Review++

What does earthquake magnitude measure? What scale measures magnitude?

- Magnitude measures the strength or amount of energy released - It's a measure of the amount of ground motion - Richter Scale measures intensity

Use the seismic wave graph on the notebook to answer the following question: How far away are you from the earthquake's epicenter when the lag time between the P and S waves is 3 min?

1900km

Use the seismic wave graph on the notebook to answer the following question: What is the arrival time of a P wave at a distance of 1000 km?

2m 10s

Use the seismic wave graph on the notebook to answer the following question: What is the distance of a P wave at 6 min?

3200 km

The two categories of seismic waves are _________________ waves and _________________ waves.

Body waves and surface waves

What is a fault?

A break in a body of rock along which one block sides relative to another, a form of a brittle strain

The earthquake shadow zone shows that a seismograph located at 125 degree around Earth from an Earthquake's focus would receive which type(s) of seismic waves, if either, from that earthquake?

A. P waves only B. S waves only C. Both p- waves and s-waves D. Neither p-waves nor s-waves =)

Based on the seismograph on the worksheet, for a given seismograph, the time elapsed between the arrival of the first p waves and the arrival of the first s waves from an earthquake focus 10,500 km away would most likely be:

A. less than 5 min B. between 5 min and 7 min C. between 8 min and 10 min D. more than 10 min =)

According to the seismograph, which of the following statements bests describe the relative amplitude of the first p waves to arrive at the seismograph and the first s waves to arrive at the seismograph? The amplitude of the first p waves to arrive at the seismograph is:

A. smaller than the amplitude of the first s waves to arrive at the seismograph =) B. larger than the amplitude of the first s waves to arrive at the seismograph C. nonzero, and the same as the amplitude of the first s waves to arrive at the seismograph D. zero, as is the amplitude of the first s waves to arrive at the seismograph

At which plate do the strongest earthquakes occur?

Convergent boundary because of the increased amount of stress on the rock

Why do Earthquakes typically occur near plate boundaries?

Earthquakes typically occur near plate boundaries because the stress on the rock is greatest

Based on the information provided, the "time earthquake starts at focus" in the seismograph corresponds to which of the following points on the seismic wave graph?

F. 0 km, 0 min =) G. 2000 km, 5 min H. 5,000 km, 12 min J. 10,000 km, 20 min

According to the shadow zone, when p waves encounter the boundary between the mantle and the core, the p waves most likely:

F. stop and do not continue into the core G. enter the core and are refracted =) H. change to s waves J. change to a third type of seismic wave

Explain the difference between the focus and epicenter of an earthquake. Display an image that labels both.

Focus- the location within Earth along a fault at which seismic activity begins and the first motion of an earhquake occurs Epicenter- the point direct on Earth's surface above the earthquake's starting point, or focus

What does earthquake intensity measure? What scale measures intensity?

Intensity is the measure of the effect of an earthquake It is dependent on: - Magnitude of earthquake - distance from the epicenter - type of rock underlying the region - construction of the building It varies on each event The Mercalli Scale measures intensity

Use the seismic wave graph on the notebook to answer the following question: What is the lag time between the P and S waves at a distance of 2400 km?

P wave - 4m 40s S wave - 8m 40s 8 40 - 4 40 ------------- 4 00 4m

List the two types of body waves.

Primary and Secondary waves

Give 3 characteristics about Primary waves.

Primary waves: - Fastest waves - Travels through solids, liquids, and gases - First waves to be detected during an earthquake - Longitudinal waves - moves rock back and forth, which streches and squeezes the rock

Give 3 or more characteristics about Secondary waves.

Secondary waves: - Slower than P waves - Travel only through solids ( cannot travel through Earth's outer core) - Second waves to be detected during an earthquake - Transverse waves - move rock side to side, which streches the rock

What type of information can seismic waves tell us about Earth's interior?

Seismic waves can tell us about the Earth's interior and the different layers inside it etc... They can also tell us about the medium in which the waves can travel through

List the places where Earthquakes are most likely to occur

Tectonic plate boundaries: Divergent oceanic environment ( mid-ocean ridge and rifts) Convergent oceanic environment (subduction zone) **Transform boundaries Continental environment ( continental movement) **Fault zone

What is the name of the major earthquake and volcano zone in the Pacific Ocean?

The Pacific Ring of Fire

Describe the relationship between the distance from the epicenter and the difference in arrival times of the P and S waves.

The farther you are from the epicenter of an earthquake, the greater the time difference between P and S waves

What is an earthquake?

The movement, trembling, or shaking of the ground that is caused by a sudden release of energy when rocks along a fault move

Describe some characteristics of surface waves.

They are the slowest moving waves, but they cause the most damage during an earthquak There are two types of surface waves: Love waves - (L) side to side motion Rayleigh waves- (R) rolling elliptical motion

Describe the behavior of S waves when they hit the outer core.

They can't get through the outer core because S waves can only travel through solids

Which region of the United Stats has the highest risk of Earthquake activity?

West coast