Where was the earthquake?

This task is about calculating and plotting data to find the epicentre of an earthquake.

An earthquake struck central New Zealand at about 11:23 a.m. yesterday morning. The time difference between the arrival of the P and S waves can be used to find the epicentre of this earthquake.

  Relationship between time difference and distance
Time between P and S waves (seconds) 12 15 18 22 26 30 35 37
Distance (km) 100 120 150 175 200 270 325 350
 
a)
 
Use this information to complete the table below which shows data collected from seismographs in three different cities.
 
Location Arrival time of waves Time difference (s)  Distance (km)
P wave (h:m:s) S wave (h:m:s)
Wellington 11:23:27  11:23:45        
Westport 11:23:30  11:23:52        
Napier 11:23:52  11:24:27    
   
b)
Use the distances you calculated, and the scale, to show where the epicentre of the earthquake was located. Use a compass to find this point and mark on the map with an X.
 
map-aotearoa-new-zealand.png