Sedimentation process in Kuala Gigieng Coast, Aceh Besar based on magnetic and gravity surveys

Abstract

The study of the sedimentation process in coastal can be used to investigate historical settlements and paleo disaster in the area. We have conducted magnetic and gravity survey to model the sedimentation process in Kuala Gigieng area, Aceh Besar, one of the important harbors during the Aceh Sultanate in 16th. The magnetic and gravity methods are able to map structures based on magnetic susceptibility and density distribution below the surface, respectively. The total magnetic field data were measured by the magnetic method, while the gravity method measured gravitational acceleration data. The data were acquired in an area of 1858 x 725 m2 with stations spacing between 70 -100 meters in grid. The standard magnetic and gravity correction was applied to the data, so that the total magnetic field anomaly and Bouguer anomaly are obtained which reflect the conditions the subsurface. The anomaly map obtained shows the pattern of maximum and minimum values, which the patterns were the same as the topography of the measurement area. To get a clearer sediment model, gravity data has been carried out 2D forward modeling with cross sections cutting from coast to land. The 2D model illustrates the existence of 3 layers in the measurement area, sequentially consisting of alluvial and clay, sandstone, and tuff sandstone sediments. The alluvial deposits in the first layer form a repetitive pattern from the land side to the coast; the pattern was formed by coastal activity. The sequence of sediment layers shows the age of the sediment, with the oldest layers formed far from the coast and the youngest layers formed near the coast.

Continuity of Great Sumatran Fault in the Marine Area Revealed by 3d Inversion of Gravity Data

“…In the fields, the physical parameters of the methods can be influenced by several factors, such as differences in elevations, latitudes, and weather, which needed to be corrected with the so-called standard corrections such as the tide, drift, free-air, Bouguer, and topographic corrections. The gravity method is a common application (2D or 3D) in a range of early explorations to study structures on either a regional scale, such as fault and basin [20], [29] or a local scale such as a shallow anomaly in archeology site [21], [22].…”

“…The gravity satellite data also used to delineate the Seulimeum and Aceh segments' structure in Sumatran Island [20]. For another case, gravity is also efficient to study the small object, i.e., archaeology [21], [22]. In this research, we study a potential use of the satellite gravity data in mapping the structure of the GSF in the marine area, which extends from Aceh Province (Indonesia) to the Andaman Islands (India).…”