The Subsurface Structure of the Lemukutan Island at the Coast and Small Islands of the Western Part of Kalimantan Waters: Inferred from Morpho-structural and SBP Analysis

Abstract

The Lemukutan Islands, located on the west coast of Singkawang, West Kalimantan. This study aims to reveal various occurrences of subsurface structures around the Lemukutan Islands waters based on morpho-structural and Sub-bottom profiler analyses. The data is then supplemented by observational data on the mainland and surrounding islands. The interpretation of SBP, DEM, and Landsat 457 composite image data reveals clear evidence of a strike-slip fault system at the west of Lemukutan Island. The fault extends to the west Penata Besar Island seabed, with a direction of N130°E. On Penata Kecil and Seluwas islands, the evidence of this structure represents brecciated sandstone. The study reveals that the strike-slip fault is indicating a movement towards NW. Traces of the strike-slip fault structure system are interpreted to have occurred post the Cretaceous period and are no longer active. The results of this research are expected to be used for disaster and environmental mitigation of coastal areas and small islands.