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Correlation between P & S Arrivals and Earthquake Depth


Charlena Sieve
Bloomington High School North

 

Problem: Is their any correlation between the depth of an earthquake and the P and S arrival times?

Objective:
• Recognize and mark the P and S arrivals on a seismogram.
• Compare and contrast the pulses represented by each of the waves associated with an event.
• Evaluate P and S arrivals and the depth of an earthquake.

Materials:
5 Seismograms
Rulers

Procedure:
1. Acquire seismograms with depth (received at the same location) from 5 different earthquakes occurring in the same region.
2. Mark the P and S waves on each of the Seismograms. Record times on data table.
3. Calculate the difference between the P and S arrival time.
4. Observe any similarities or major differences in the P or S waves either within the individual seismogram or among all 5. Record observations.
5. Record depth listed on each seismogram in data table. Note which category the depth occurs:
Shallow <70 Km
Intermediate 70 – 300 Km
Deep > 300 Km

Observations:

Earthquake                           Seismograph Similarities                                        Seismograph Differences

 

 

 

 

 

 

 


Data Table:

Earthquake location

Date/Time

Latitude
Longitude
Magnitude
Depth of Earthquake
P-wave Arrival Time
S-wave Arrival Time
Difference Between P & S Arrival
               
               
               
               
               


Analysis Questions:

1. Is there a correlation between the arrival times of the P waves and the depth of the earthquake?
2. Is there a correlation between the difference between the P and S waves and the depth of the earthquakes?
3. Were there any observable similarities on the seismograms of the deep earthquakes?
4. Were there any observable differences between the seismograms based on their depth?
5. Did any of these earthquakes coincide with a plate boundary? If so, which ones?


Conclusion:

Teacher Notes

There are several variations to this Lab. Students can use seismograms which you have printed off for this activity. Students can use the Eqlocate program to assist them in this activity. Students can go into the IRIS Homepage and find events of interest which you can download, and be viewed in the Winquake program for this activity.

 


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