Geology books have call numbers starting with QE and are located on the 4th floor of the library
QE1-350.62 General, Including geographical divisions
QE500-639.5 Dynamic and structural geology
QE521-545 Volcanoes and earthquakes
QE601-613.5 Structural geology
You might also find related topics filed under GB for physical geography, and QC851-999 for meteorology and climatology.