According to a spokesman for Universal Studios, the small interior fire caused minimal damage. It was contained and extinguished by the emergency sprinkler system.
Initial reports indicate that electrical wiring may be to blame.
The spokesman said the theme park is open on Friday, and the earthquake attraction is expected to be reopened this weekend.
The backlot was the scene of a huge fire back in 2008. That fire started along what's known as New York Street, and then jumped over to Courthouse Square.
A number of historic sets and attractions were destroyed. But a lot of rebuilding was done, and it has since reopened.