block-fault mountain

A block-fault mountain is formed when blocks of Earth's crust are uplifted or tilted due to faulting. These mountains can also form when blocks are pulled apart, causing the land between them to subside and form a valley, while the remaining elevated blocks become mountains.12

These elevated blocks are known as horsts, and they are characterized by steep slopes on both sides. Conversely, the subsided areas between these blocks are called grabens, which can form rift valleys. Block faulting can result in isolated mountains or ranges that form a larger mountain belt. Examples include the Tetons and the Sierra Nevada in the United States, where blocks tilted up on one side created steep eastern slopes.32