Armenia Fault

Armenia Fault
Armenia Fault
Falla de Armenia
Etymology	Armenia
Coordinates	04°28′45″N 75°42′21″W / 4.47917°N 75.70583°W
Country	Colombia
Region	Andean
State	Quindío
Cities	Armenia
Characteristics
Range	Central Ranges, Andes
Part of	Romeral Fault System
Length	~32 km (20 mi)
Strike	023.2 ± 11
Dip	Very high
Dip angle	West
Displacement	0.1 mm (0.0039 in)/yr
Tectonics
Plate	North Andean
Status	Active
Type	Oblique strike-slip fault
Movement	Normal sinistral
Age	Quaternary
Orogeny	Andean

The Armenia Fault (Spanish: Falla de Armenia) is an oblique sinistral strike-slip fault in the department of Quindío in west-central Colombia. The fault is part of the megaregional Romeral Fault System and has a total length of approximately 32 kilometres (20 mi) and runs along an average northwest to southeast strike of 023.2 ± 11 in the Central Ranges of the Colombian Andes. The fault shows Holocene activity with a surface rupture produced in 2001.

Etymology

The fault is named after Armenia, the capital of Quindío.^[1]

Description

The Armenia Fault is part of the Romeral Fault System on the western slope of the Central Ranges of the Colombian Andes. The fault crosses the city of Armenia and displaces Pliocene to Pleistocene volcanic and volcano-sedimentary deposits of the Quindío Fan (Spanish: Abanico del Quindío), which covers about 400 square kilometres (150 sq mi). The geometric and neotectonic features of the Montenegro and Armenia Faults are very similar.^[1]

The fault forms well-developed fault scarp as much as 50 metres (160 ft) high, characterised by beheaded streams, ponded alluvium, aligned and offset drainages, soil and rock slides on the face of the scarp, and localised tilting of terrain. The Armenia Fault deforms Quaternary volcano-sedimentary debris flow and pyroclastic flow deposits.^[1] The valley of the Quindío River follows the strike of the Armenia Fault.^[2]

Activity

The fault is considered active with Holocene tectonic movement. A trench opened in April 2001 near Circasia, about 20 kilometres (12 mi) north of Armenia,^[3] indicating that the fault last movement is younger than 4,820 years (and probably less than 3,000 years) based on a previously dated bed of lapilli that was erupted by the Machín volcano.^[4] A maximum moment magnitude of 6.5 to 6.8 and a recurrence interval of 1000 years is estimated for this fault, based on the length of Quaternary rupture and displacement of topographic features at the fault.^[1]