To remove a Caltrics subscription from Google calendar, LOG IN to your Google calendar.
On the Google calendar Main menu (click ‘hamburger’ icon to reveal) under ‘Other calendar‘ you will see your ‘Caltrics‘ account listed (or the name to which you may have changed it).
Hover over ‘Caltrics’ and click on the ‘X‘ that is revealed, to ‘Unsubscribe from Caltrics‘ .
In the confirmation box, click on ‘Remove calendar‘