Event for Geolocation Changed.

Question

Hello,

Any body please tell me that is there any event for the Geolocation Changed in Windows Phone 8 (C#)? 

That is I want to trigger some event when the Geolocation is changed Like City from Reversegeocoding changed.

If not , then is it possible to generate some Events Events manually whenever the Phone's Location like City is Changed.

(suppose i have fetched the  City using Reverse Geocoding). (for Windows Phone 8)

Please help me .