The radius search is managed from Search Settings -> Geolocation Settings and applies only for the half map style page (advanced search results, properties list half-page and taxonomy half-if that is enabled)
You can enable/disable this option entirely, you can show the radius in miles or km, you can set the minim and maxim radius value as well as the initial radius value.
Also can choose between to system types for geolocation: google places or open street
You can set up it from Theme options -> Map -> Map Settings:
How Geolocation is displayed:
- When have google places enabled as a system type for geolocation:
- When have open street enabled as system type for geolocation:
How to change the color of the geolocation radius