Question

date:
graded assignment
lab report: earthquake epicenter
answer the questions below. when you are finished, submit this assignment to your teacher by the due date for full credit.
in this laboratory experiment, you will be working as an amateur seismologist to locate the epicenter of a fictional earthquake. your task will involve interpreting seismograms from three seismograph stations; determining the difference - in - time between the arrival of the p waves and arrival of the s waves from the earthquake; using a travel - time graph to determine how far each seismograph station is from the epicenter; and using the technique of triangulation to pinpoint the location of the quake.
step 1: interpreting the seismograms

1. estimate the times of the first arrival of the p waves and the s waves at each seismograph station. enter these times into your data table. reminder: you are trying to find the difference between the arrival time of the p wave and the s wave.
2. determine the difference between the arrival of the p wave and the arrival of the s wave, and enter this difference into the data table.

example:
tulsa, oklahoma
8:06 8:07 8:08 8:09 8:10 8:11
the p wave arrived at 8:06:00, and the s wave arrived at 8:10:30.
the difference is 2 minutes and 30 seconds, or 2 1/2 minutes.
step 2: determining the distance to the epicenter
you now know the difference between the arrival of the first p wave and the first s wave for each seismic station. because the waves travel at a known speed, this interval can be converted to distance using the graph below.
example:
tulsa, oklahoma
8:06 8:07 8:08 8:09 8:10 8:11
the p wave arrived at 8:08:00, and the s wave arrived at 8:10:30.
2 1/2 minutes

Explanation:

Step1: Estimate arrival times

For each seismograph station, identify the time of first - arrival of P - wave and S - wave from the seismogram and record in the data table.

Step2: Calculate time difference

Subtract the arrival time of the P - wave from the arrival time of the S - wave for each station. For example, if P - wave arrives at 8:06:00 and S - wave arrives at 8:10:30, the difference is \(8\colon10\colon30 - 8\colon06\colon00=4\) minutes and \(30\) seconds or \(4.5\) minutes. Enter this value into the data table.

Step3: Determine distance to epicenter

Use the known speed of the waves and the time - interval (difference between P - and S - wave arrival times) for each station. Locate the time - interval on the travel - time graph and read off the corresponding distance from the graph for each station. This distance represents how far each seismograph station is from the epicenter.

Since no specific data for other stations is given in the provided text, we can't give a final numerical answer. But the general steps for answering the questions in the lab report are as above.

Answer:

Step1: Estimate arrival times

For each seismograph station, identify the time of first - arrival of P - wave and S - wave from the seismogram and record in the data table.

Step2: Calculate time difference

Subtract the arrival time of the P - wave from the arrival time of the S - wave for each station. For example, if P - wave arrives at 8:06:00 and S - wave arrives at 8:10:30, the difference is \(8\colon10\colon30 - 8\colon06\colon00=4\) minutes and \(30\) seconds or \(4.5\) minutes. Enter this value into the data table.

Step3: Determine distance to epicenter

Use the known speed of the waves and the time - interval (difference between P - and S - wave arrival times) for each station. Locate the time - interval on the travel - time graph and read off the corresponding distance from the graph for each station. This distance represents how far each seismograph station is from the epicenter.

Since no specific data for other stations is given in the provided text, we can't give a final numerical answer. But the general steps for answering the questions in the lab report are as above.