Decomposing Worldwide Complete Spherical Bouguer Gravity Anomaly Using 2-D Empirical Method

Southeast Asian Conference on Geophysics

Firdaus, Ruhul^1 ; Mey Ekawati, Gestin^1

Department of Geophysical Engineering, Faculty of Science, Institut Teknologi Sumatera, Jl. Terusan Ryacudu, Desa Way Hui, Kecamatan Jati Agung, Lampung Selatan

35365, Indonesia^1

关键词: Body distributions;    Bouguer gravity anomalies;    Earth gravity field;    Geophysical applications;    Mono-component signal;    Prior information;    Processing technique;    Satellite measurements;   

Others  :  https://iopscience.iop.org/article/10.1088/1755-1315/62/1/012045/pdf
DOI  :  10.1088/1755-1315/62/1/012045

来源: IOP

【 摘 要 】

Currently available worldwide gravity anomaly data provides a high-resolution (2'×2') of Complete Spherical Bouguer Anomaly (CSBA) based on the available information of the Earth gravity field from surface and satellite measurements. The data has not only been provided and processed thoroughly but it also has been claimed to be appropriate for various geophysical applications. Therefore, the analysis of gravity anomaly is becoming increasingly significant for the earth sciences as a whole and assisting both shallow and deep geological problems. Earth gravity anomaly has to be analyzed carefully as it has very complex data due to anomaly mixing of the density masses spread over the Earth horizontally and vertically. The bigger the spatial coverage of data (e.g. global scale data), the more severe the data from anomaly mixing due to various wavelength. BEMD is an empirical method supposedly suitable with highly oscillation-mixing data. It can effectively isolate each local anomaly in details and is analogized as successively reverse moving average with local windowing. BEMD is designed to reduce multi-component, non-linear gravity field data to a series of single local anomaly contributions. Anomaly from a single body was assumed as a mono-component signal. The main advantage of BEMD processing techniques is to present the subtle details in the data which are not clearly identified in anomaly maps, without specifying any prior information about the nature of the source bodies. As the result, we have identified regional anomalies due to the drift of continental and oceanic masses considered as crust-regional anomaly (CRA). We remove the CRA from the CBA to provide surface-residual anomaly (SRA) where shallow geologic bodies reveal. Meanwhile, the CRA itself can be used as reference to reduce this high magnitude anomaly from any measurement data to exhibit only shallow body anomaly. Further analysis can be carried out to build a general understanding of the details and parameters of the shallower or deeper causative body distributions.