Gravity Analysis for Subsurface Characterization and Depth Estimation of Muda River Basin, Kedah, Peninsular Malaysia

Abstract

Gravity survey is one of the passive geophysical techniques commonly used to delineate geological formations, especially in determining basement rock and the overlying deposit. Geologically, the study area is made up of thick quaternary alluvium deposited on top of the older basement rock. The Muda River basin constitutes, approximately, of more than 300 m of thick quaternary alluvium overlying the unknown basement rock type. Previous studies, including drilling and geo-electrical resistivity surveys, were conducted in the area but none of them managed to conclusively determine the basement rock type and depth precisely. Hence, a regional gravity survey was conducted to determine the thickness of the quaternary sediments prior to assessing the sustainability of the Muda River basin. Gravity readings were made at 347 gravity stations spaced at 3–5 km intervals using Scintrex CG-3 covering an area and a perimeter of 9000 km2 and 730 km, respectively. The gravity data were then conventionally reduced for drift, free air, latitude, Bouguer, and terrain corrections. These data were then consequently analyzed to generate Bouguer, regional and total horizontal derivative (THD) anomaly maps for qualitative and quantitative interpretations. The Bouguer gravity anomaly map shows low gravity values in the north-eastern part of the study area interpreted as representing the Main Range granitic body, while relatively higher gravity values observed in the south-western part are interpreted as representing sedimentary rocks of Semanggol and Mahang formations. Patterns observed in the THD anomaly and Euler deconvolution maps closely resembled the presence of structural features such as fault lineaments dominantly trending along NW-SE and NE-SW like the trends of topographic lineaments in the study area. Based on power spectral analysis of the gravity data, the average depth of shallow body, representing alluvium, and deep body, representing underlying rock formations, are 0.5 km and 1.2 km, respectively. The thickness of Quaternary sediment and the depth of sedimentary formation can be more precisely estimated by other geophysical techniques such as the seismic reflection survey.

Understanding the Deep Structure of the Essaouira Basin Using Gravity Data: Hydrogeological Inferences for a Semiarid Region in Central-Western Morocco

“…Nowadays, ED is extensively employed as a powerful method for automatically interpreting potential field data, owing to its notable simplicity in usage and implementation [4,50]. This method helps to delineate geological structures by determining their positions and depths, as well as the extent of their roots [51][52][53]. The positive outcomes of its utilization for the interpretation of potential field data have been thoroughly documented across multiple research studies [40,[54][55][56][57].…”

Contribution of Gravity Data for Structural Characterization of the Ifni Inlier, Western Anti-Atlas, Morocco: Hydrogeological Implications

“…These gradient zones indicate boundaries between blocks of varying densities, and maxima typically indicate them (Figure 4a). For this study, we applied the THG technique to the residual anomaly map, using Equation ( 1) [18,23,27,28,36,65].…”

“…The Euler deconvolution technique, initially proposed by Thompson [66], is a filtering method that facilitates the characterization of geological structures by enabling the detection of their location, determining their depth, and identifying their degree of rooting (Figure 4a) [17,18,67]. Numerous research studies have extensively validated this technique [11,13,29,30,[68][69][70].…”

“…This study aims to use gravity data analysis to create a detailed map of the fault systems affecting the study area for hydrogeological reconnaissance purposes [11][12][13][14][15]. The residual gravity data, derived from subtracting the regional anomaly component from the Bouguer anomaly map, is analyzed using different transformation techniques to analyze the gradient of the gravity field [13,[16][17][18][19][20][21][22][23][24][25][26]. The Horizontal Gradient filter transforms the inflection point of the residual gravity profile into a positive anomaly whose maximum coincides with the fault location, while the Tilt derivative filter is used to confirm the fault position [26][27][28][29][30].…”

Physical modeling of magma chamber of slamet volcano by means of satellite gravimetric data

“…Some corrections commonly applied to the gravitymeter such as equipment elevation correction and drift correction were also not required [21]. Hence, it was only Bouguer and terrain corrections applied in data processing to obtain Complete Bouguer Anomaly (CBA) data [22] representing the presence of areas of locally high or low density in the subsurface of the Earth [23,24].…”