The faculty building "Ke Karlovu 3" is filled with red. It can be reached by walk from the subway stations "I.P.Pavlova" or "Vysehrad", line C.
When entering the faculty building "Ke Karlovu 3", you should pass through the corridor in the first (slightly higher than the entrance) or second floor across the building to the back staircase and go upstairs to the third floor. The Department of Geophysics is located directly at the back staircase.
Note that a better quality GIF version of the above map (165 kB!) is also available.