Earthquake Worksheet

1. Observe the three circles you have drawn. Where is the earthquake's epicenter? The Earthquakes epicenter is in Kentucky because all the circles i drew around the hits meet in Kentucky.

2. Which city on the map is closest to the earthquake epicenter? How far in kilometers is this city from the epicenter?

It is Chicago and it is located 600 kilometers away from Chicago.

3. In which of the three cities listed in the data table would seismographs detect the earthquake first and last?

The first place the seismographs would detect the earthquake in is Chicago because of the close distance. The last one is Denver because it is the farthest. And obviously the second in Houston because it is in between.

4. About how far from San Francisco is the epicenter you found? What would be the difference in arrival times of the P waves and S waves for a recording station in San Francisco?

The epicenters is roughly 3,200 kilometers away from Chicago that means it take 4.4 minutes for the waves to arrive. P waves (primary waves) can travel through anything no matter if it is sold or liquid, however secondary waves (S waves) cannot. In San Francisco the primary waves would arrive a lot earlier than S waves because they travel faster going through both solids and liquids while S waves can only travel through solid.

5. What happens in arrival times between P waves and S waves as the distance from the earthquake increases?

While the distance from the earthquake is increasing the force is setting lower and its going farther away from the epicenter. P waves will still have the advantage of distance but they wont travel as fast because they don’t have enough or as much energy. When S and P waves meet, surface waves are formed.

6. Review the procedure you followed in this lab and then answer the following question. When you are trying to locate an epicenter, why is it necessary to know the distance from the epicenter for at least three recording stations?

If a station only had one hit for an earthquake they will not know where the epicenter si exactly, it could be anywhere within in the circle. When you have ti from 3 stations you can see that the path the earthquake was taking and the vibrations that it made. The you join them all together to find the epicenter.

Finding the epicenter without 3 points is very close to hard. If a stations only has 1 hit of the earthquake, they will not know where exactly the epicenter was, it could be anywhere in the circle. Having found recordings from 3 recording stations, one may see the path the earthquake is going and its vibrations, and then join all of the points together to find the exact epicenter!