Question

determining distance from s-p
use the s-p graph to the left and the estimates you made for the s-p time intervals for the three seismograms (shown again for your convenience) to complete the table below. the horizontal grid is in one second intervals. then click the find epicenter button.

station	s-p interval	epicentral distance
las vegas, nv	40 seconds	_______ km
phoenix, az	60 seconds	_______ km

find epicenter button image

graph: time (seconds) on y-axis (30 - 70), distance (kilometers) on x-axis (300 - 700), with s-p line plot

Explanation:

Step1: Locate S-P interval on y - axis

For Fresno, CA and Las Vegas, NV with S - P interval of 40 seconds, and Phoenix, AZ with 60 seconds.

Step2: Draw horizontal line from y - axis value

Draw a horizontal line from 40 seconds on the y - axis (for Fresno and Las Vegas) and 60 seconds (for Phoenix).

Step3: Find intersection with graph and read x - value

For 40 seconds: Intersection with the graph gives approximately 400 km. For 60 seconds: Intersection gives approximately 600 km.

Answer:

Fresno, CA: 400 KM; Las Vegas, NV: 400 KM; Phoenix, AZ: 600 KM