Power Spectrum Analysis of the Satellite Gravity Anomalies Data to Estimate the Thickness of Sediment Deposits in the Purwokerto-Purbalingga Groundwater Basin

Abstract

Analysis of power spectrum of the satellite gravity anomalies data has been carried out to estimate the thickness of sediment deposits in the Purwokerto-Purbalingga Groundwater Basin. Power spectrum analysis uses the Fourier transform principle by converting data from the space domain to the frequency domain. Spectrum analysis has been done on all trajectories placed on the gravity anomaly map which has been corrected and transformed on the horizontal surface. The gradient of the gravity anomalies data spectrum graph is proportional to the depth of the anomaly source boundary plane. The calculation results show that the average depth of the boundary plane of the local anomaly source for each trajectory is 470.89 m. This depth is calculated from the topographic surface, so that this value indicates the thickness of sediment deposits in the Purwokerto-Purbalingga Groundwater Basin.