P Wave S Wave Lag Time

A P-wave takes 5 minutes to travel from the epicenter of an earthquake to a seismic station. Approximately how many minutes will it take an S-wave to travel that same distance?

• 15 min
• 12 min
• 9 min
• 4 min

The map below shows changes in the position of the tsunami wave front produced by the 1964 Alaskan earthquake. The numbers indicate the time, in hours, for the wave front to reach the positions indicated by the isolines. If the wave front reached the Hawaiian Islands at 10:30 p.m., at approximately what time did the earthquake occur?

• 1:30 p.m.
• 5:30 p.m.
• 3:30 a.m.
• 4:30 a.m.

What is the approximate P-wave travel time from an earthquake if the P-wave arrives at the seismic station 8 minutes before the S-wave?

• 4 minutes 20 seconds
• 6 minutes 30 seconds
• 10 minutes 0 seconds
• 11 minutes 20 seconds

Base your answers to questions 43 through 45 on the diagram below and on your knowledge of Earth science. The diagram represents a cut-away view of Earth’s interior and the paths of some of the seismic waves produced by an earthquake that originated below Earth’s surface. Points A, B, and C represent seismic stations on Earth’s surface. Point D represents a location at the boundary between the core and the mantle. Seismic station A is 5000 kilometers from the epicenter. What is the difference between the arrival times of the first P-wave and the arrival time of the first S-wave recorded at this station?

• 2 minutes 20 seconds
• 6 minutes 40 seconds
• 8 minutes 20 seconds
• 15 minutes 00 second

Which process prevented P-waves from arriving at seismic station B?

• Refraction
• Reflection
• Convection
• Conduction

Only P-waves were recorded at seismic station C because P-waves travel

• Only through Earth’s interior, and S-waves travel only on Earth’s surface
• Fast enough to penetrate the core, and S-waves travel too slowly
• Through iron and nickel, while S-waves cannot
• Through liquids, while S-waves cannot

A seismic P-wave is recorded at 2:25 p.m. at a seismic station located 7600 kilometers from the epicenter of an earthquake. At what time did the earthquake occur?

• 2:05 p.m
• 2:11 p.m
• 2:14 p.m.
• 2:36 p.m.

A seismic station recorded the P-waves, but no S-waves, from an earthquake because S-waves were

• absorbed by Earth’s outer core
• transmitted only through liquids
• weak and detected only at nearby locations
• not produced by this earthquake

If a seismic station is 3200 km from an earthquake epicenter, what is the time needed for an S-wave to travel from the epicenter to the seismic station?

• 4 min 40 sec 
• 6 min 0 sec 
• 10 min 40 sec
• 11 min 10 sec

The epicenter of an earthquake was located 1800 kilometers from a seismic recording station. If the S-wave arrived at the seismic station at 10:06:40 a.m., at what time did the P-wave arrive at the same seismic station?

• 10:03:00 a.m.
• 10:03:40 a.m.
•  10:09:40 a.m.
• 10:10:20 a.m.