Chapter 10: Problem 15

On the seismogram of an earthquake recorded at a seismic station in Paris, France, the S-wave arrives six minutes after the P-wave. On the seismogram obtained by a station in Mumbai, India, for the same earthquake, the difference between the P-wave and S-wave arrival times is 4 minutes. Which station is closer to the epicenter? From the information provided, can you pinpoint the location of the epicenter? Explain.

Short Answer

Expert verified

The Mumbai seismic station is closer to the epicenter, as it has a smaller difference in P-wave and S-wave arrival times (4 minutes) compared to the Paris station (6 minutes). Despite this information, we cannot pinpoint the location of the epicenter, as we would need additional data from more seismic stations and apply a technique called "triangulation" using at least three stations to determine the exact location.

Step by step solution

Seismograms record the waves generated by earthquakes. There are two primary types of seismic waves: P-waves (also called primary waves) and S-waves (also called secondary waves). P-waves travel faster than S-waves, and they arrive at seismic stations before S-waves. The difference in arrival times between P-waves and S-waves can be used to determine how far a seismic station is from the epicenter of an earthquake. #Step 2: Analyzing the time difference between P-wave and S-wave arrivals#

At the Paris seismic station, the time difference between the arrival of the P-wave and S-wave is 6 minutes. At the Mumbai seismic station, this time difference is 4 minutes. Since P-waves travel faster than S-waves, a smaller difference in arrival times at a station indicates that the station is closer to the epicenter. #Step 3: Determining which station is closer to the epicenter#

Comparing the time differences, we find that the Mumbai station (4 minutes) has a smaller difference in P-wave and S-wave arrival times than the Paris station (6 minutes). Therefore, the Mumbai station is closer to the epicenter of the earthquake. #Step 4: Discussing the possibility of pinpointing the epicenter location#

While we have determined which station is closer to the epicenter, we still do not have enough information to pinpoint the exact location of the epicenter. By knowing the time differences in P-wave and S-wave arrivals, we can only estimate the distance to the epicenter, not the specific location. To determine the exact location of the epicenter, we would need additional data from more seismic stations. A technique called "triangulation" is often used to determine the epicenter location by analyzing the data from at least three seismic stations.