Answer Happy

Earthquakes Locating Earthquake Epicenter 1. Four partial records of the same earthquake were recorded at Los Angeles, San Francisco, Salt Lake City, and Albuquerque, shown below. Determine the lag time for each recording station and enter it into the "lag time" column, by subtracting the S-wave arrival time from the P-wave arrival time. Recording Station P-wave arrival time Los Angeles San Francisco Salt Lake City Albuquerque 11:06:06 PST 11:06:46 PST 12:08:06 MST 12:08:45 MST S-wave arrival time 11:06:19 PST 11:07:18 PST 12:09:22 MST 12:10:21 MST P-waves took how many seconds? Lag time? 2. Assuming an average velocity of 3.80 miles/second for the P-waves, and 2.54 miles/second for the S-waves, how long does it take for each type to travel 100 miles? Show how you arrived at your answer. S-waves took how many seconds? What is the lag time associated with this distance (100 miles)? seconds seconds seconds seconds
3. Determine the distance from each of the four seismograph stations to the epicenter of the earthquake. Distance may be computed by proportion, using the lag time value to 100 miles that you obtained in Problem 2. Recording Station Los Angeles: San Francisco: Salt Lake City: Albuquerque:: Calculated Distance (miles)? miles miles miles miles 4. On the base map of the western United States (Figure 4, at the bottom of this worksheet), draw circles or arcs with a compass, locating the needle point at each of the four stations, with each radius corresponding to the calculated distance (use the graphic scale on the base map for measurement). (hints for drawing: either save this figure/doc in a word document or other program and draw the figure there or print it out and then take a picture and submit back in). However, you could also use a free program called Google Earth Pro. I include a tutorial of how to do this in Google Earth Pro in my video for this assignment. Realize that Google Earth Pro does not like web based devices (i.e. Chromebooks, tablets, and phones). Where is the epicenter located (draw a star on your map)? Which of these 4 cities is the earthquake epicenter closest to, and how far is it (miles)? 5. Considering the cause of earthquakes discussed during lecture, what major structural feature is probably related to this earthquake? 6. The time at which the P-wave arrived at each of the four stations is shown on the seismograph record (Problem 1). But when did the earthquake actually occur? Show how you obtained your answer.
San Francisco 0 100 Los Angeles 200 300 400 500 Miles Salt Lake City ● Albuquerque Figure 4: Base Map of western United States