page_title: Nias Basin
section_title: Geologic structures
hierarchical_section_title: Nias Basin / Geologic structures
caption_attribution_description: English: Cross-section of Nias Basin from the Mentawai Fault to Panjang
context_page_description: The Nias Basin is a forearc basin located off the western coast of Sumatra, Indonesia, in the Indian Ocean. The name is derived from the island that bounds its western edge, the island of Nias. The Nias Basin, the island of Nias, and the offshore, submarine accretionary complex, together form a Forearc region on the Sunda Plate/Indo-Australian Plate collisional/subduction boundary. The Forearc region is the area between an oceanic trench and its associated volcanic arc. The oceanic trench associated with the Nias Basin is the Sunda Trench, and the associated volcanic arc is the Sunda Arc.
  The Nias Basin itself is structurally bounded to the west by the Mentawai Fault and bounded to the east by the Volcanic Arc island of Sumatra. It is a geologically independent basin from its neighbor basins; the Simeulue Basin to the north, and the Mentawai and Enggano Basin to the south. The Nias Basin spans ~250 kilometer length-wise, and ~100 kilometers width-wise. Overall, the Nias Basin can be divided into two sub-basins; the Singkel Basin to the north, and the Pini Basin to the south.
context_section_description: The Nias Basin is an asymmetric basin, with the Mentawai Fault bounding its Western edge. The Mentawai Fault is a transform fault that parallels the Sunda Trench, and separates the accretionary complex of the fore-arc, from the fore-arc basin. This fault is the result of the oblique subduction nature of the Indo-Australian Plate. The Mentawai Fault also has a normal fault component to its behavior as well, assisting in the formation of the fore-arc basin, as well as creating more space for sediment deposition and subsidence. The motion of the Mentawai Fault also results in accessory faults within the Nias Basin itself. These faults are also normal/transform in nature, and are the faults that bound the 2 sub-basins within the Nias Basin. These smaller faults form ~30 degrees to the Mentawai Fault, and create graben-like structures.
caption: Cross Section Of Nias Basin[1]
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