1. Gravity Theory Measurement practices –Relative –Closed loops Corrections –Drift –Free Air –Bouguer –Terrain Interpretation –Modeling

13. Worden Gravimeter

14. Inside the Worden

18. Closing the Loop

19. Elevation Corrections Free Air Correction Bouguer Correction

20. Gravity Corrections Drift Correction (t obs -t base ) x drift rate Free Air Correction (h obs -h base ) * 0.3086 mgal/m Bouguer Correction (h obs -h base ) * 0.04193  mgal/m where  = density in gr/cc

21. Gravity Anomalies Free Air Anomaly  g fa = (g obs -g base ) – (drift corr) + (fa corr) Bouguer Anomaly  g b =  g fa –(bouguer correction)

22. Gravity Corrections (sample)