24.14.1. Concept of Isochrons

Try these first

1. 1.

   What does an isochron represent?

   Hint

   Think about how we measure time.

2. 2.

   Name one type of seismic wave.

   Hint

   These waves are important in understanding earthquakes.

3. 3.

   What do isochrons represent?

   • Points of equal wave arrival time
   • Types of seismic waves
   • Locations of earthquakes

   Hint

   Think about a map showing seismic wave arrival.

4. 4.

   True or False: Isochron maps only provide information on P-waves.

   • True
   • False

   Hint

   Consider all types of seismic waves.

5. 5.

   Given a travel-time curve indicates that P-waves travel at 5 km/s, and a station recorded arrival in 15 seconds, determine the distance from the epicenter.

   Hint

   Use the formula to find the distance.

6. 6.

   An earthquake's epicenter is located 10 km away. If the S-wave arrival time is 20 seconds, estimate using a travel-time curve that shows S-waves move at 3 km/s whether this is reasonable.

   Hint

   Compare different velocities of waves.