is it possible to merge duplicate event locations?
Location details for events are stored in a sql table called civicrm_loc_block which brings together an address an email and a phone number for each event.

At a push you could identify the affected events and update them so they all share the same loc_block id. But that would need to be done by querying/updating the SQL tables.

Basically, there isn't a function to address this in the user interface.