24.3.1. Triangulation Method Using Seismic Stations

Try these first

1. 1.

   What does the triangulation method use to find an epicentre?

   Hint

   Think about what information is needed to determine a distance.

2. 2.

   Which seismic wave arrives first at seismic stations?

   Hint

   Remember, P is for Primary, which means first!

3. 3.

   What key method is used for locating earthquake epicentres?

   • Triangulation
   • Geolocation
   • Topography

   Hint

   Consider which method uses three points for location.

4. 4.

   True or False: Triangulation requires at least two seismic stations.

   • True
   • False

   Hint

   Think about how many points are necessary for triangulation.

5. 5.

   If two seismic stations recorded P-wave and S-wave arrival times of 2s and 6s, and 3s and 9s respectively, discuss how you would apply the triangulation method. What discrepancies would you expect due to distance?

   Hint

   Consider the role of distance and placement when using waves' arrival times.

6. 6.

   Imagine you are a seismologist. Given a seismic station is 50 km away from the epicentre and recorded P-wave arrival time as 5 seconds, calculate the expected S-wave arrival time, given S-waves travel at 60% the speed of P-waves which travel at approximately 8 km/s.

   Hint

   Use the formula for time = distance / speed and remember the relationship between P-waves and S-waves.