What geological feature is formed from parallel normal faults?

A graben is a geological feature that is formed as a result of parallel normal faults. When tectonic forces pull the Earth's crust apart, it causes blocks of the crust to drop down between these faults. This dropping block creates a low-lying area known as a graben, which is typically characterized by its length and the parallel orientation of the faults on either side.

In contrast, a rift valley is more commonly associated with large-scale tectonic rifting, where a larger area sinks down, but a graben specifically refers to the smaller, more localized sections between two normal faults. A horst is the opposite of a graben; it's a raised block of the Earth's crust located between two normal faults. An earthquake zone describes areas where seismic activity frequently occurs, but it does not specifically denote a geological feature formed by parallel normal faults. Hence, the formation of a graben by parallel normal faults is the most accurate description of this geological phenomenon.