To find the distance to the earthquake, we need to use the graph provided. Here is the step-by-step process:
1.
Identify the Time: Look at the seismogram (the small box with the wiggly lines) in the top left corner. It states that the time difference between the arrival of the P wave and the S wave is
4 minutes and 15 seconds. This is often called the "S-P interval."
2.
Locate the Time on the Graph: Look at the vertical axis (y-axis) on the left, which represents "Time after earthquake, in minutes." Find the mark for 4 minutes and 15 seconds. Since each major grid line is 5 minutes, 4 minutes and 15 seconds is a bit below the "5" mark.
3.
Find the Matching Gap: The blue curve represents the S Wave and the red curve represents the P Wave. We need to find the specific point on the horizontal axis (x-axis) where the vertical gap between the blue curve and the red curve equals exactly 4 minutes and 15 seconds.
* At 2000 km, the gap is roughly 3 minutes.
* At
3000 km, if you look straight up, the P wave (red line) is at about 5.5 minutes and the S wave (blue line) is at roughly 9.5 to 10 minutes. The difference here is approximately 4 to 4.5 minutes.
* Let's check standard seismic data values usually associated with these graphs: An S-P interval of roughly 4 minutes corresponds very closely to a distance of
3000 kilometers.
4.
Read the Distance: Follow the vertical line down from that point on the curves to the horizontal axis (x-axis). The value aligns with
3000.
Therefore, the epicenter of the earthquake is 3000 kilometers away.
Final Answer:
3000 kilometers
Parent Tip: Review the logic above to help your child master the concept of earthquake p wave and s wave travel time worksheet.
