While there is no explicit reference to H. P. Lovecraft neither in the credits nor in the titles, around the minute 16 you can see the protagonist hanging on the wall her title awarded by the Miskatonic University, a fictional place recurrently mentioned in Lovecraft's stories.
During the scene where Matthew is struggling to open a bottle of wine, the label on the bottle names the brand 'Herbert West', a reference to the lead character from the Lovecraft inspired film Re-Animator (1985) which also follows the story of a mad scientist.
A further connection to Lovecraft occurs about min. 46. The keychain Olive holds up has a tiny Cthuhlu pendant on it.
For the location shots of the city, the production crew filmed in both Hull and York so the crew referred to the fictional city in the movie as Hawk, an amalgamation of both real world cities.
The diving suit costume Anna Dawson wears in the opening sequence of the film was originally created as a Mr. Freeze costume from the video game Batman: Arkham City (2011) to be used for Cosplay and was heavily modified for use in this movie.