Seismic Zones in Canada?

[m63]

I've had this thread in 'structural engineering other topics', but no replies. I hope for better response in this forum:
Am I right thinking that one place in Canada belongs to two different seismic zones if it has different Za and Zv values? And than, how and when would you differentiate in practice, what seismic zone would you assign to Ottawa for example(Za=4, Zv=2)? In another words, what determines seismic zone in general: Za or Zv?

 

[eureka]

See "International Handbook of Earthquake Engineering", Edited by Mario Paz. Chapter 9 covers Canada. I think you will find answers to your questions.