page_title: Graben
section_title: Half-graben
hierarchical_section_title: Graben / Half-graben
caption_attribution_description: USGS cross-section of the Newark Basin.
context_page_description: In geology, a graben is a depressed block of the crust of a planet bordered by parallel faults.
context_section_description: In many rifts, the graben are asymmetric, with a major fault along only one of the boundaries, and these are known as half-graben. The polarity (throw direction) of the main bounding faults typically alternates along the length of the rift. The asymmetry of a half-graben strongly affects syntectonic deposition. Comparatively little sediment enters the half-graben across the main bounding fault because of footwall uplift on the drainage systems. The exception is at any major offset in the bounding fault, where a relay ramp may provide an important sediment input point. Most of the sediment will enter the half-graben down the unfaulted hanging wall side (e.g. Lake Baikal).
caption: The Newark Basin, an early Mesozoic half-graben
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