You can manage which calendar notifications you receive using the Google Calendar web application. By default, you will received notifications for your personal calendar only. You will need to enable notifications if you wish to receive them for any additional calendars that have been shared out to you.
Click the Settings
link located in the My calendars
section of the Google Calendar web application.
Click the Notifications
link to the right of the calendar for which you wish to manage notifications.
(check box) for each notification you wish to enable.
Click the Save
Click the Back to calendar