Is there an option to do this?
Or is there a way to log whenever someone (teacher or admin) alters the gradebook? For transparency purposes
The grade_grades_history table keeps a record of all changes to grades, unless you tell it not to. This is controlled by the settings in Site Administration -> Server -> Cleanup
is there a page that allows me to view this? or is it just database logging?
I've not seen a page that displays the history, although it would be easy enough to write one using the Ad-hoc database queries plugin.