The Irlanda Fault () is a dextral

strike-slip fault In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust result from the action of plate tectonic ...

in the department of Cauca in south-central

Colombia Colombia, officially the Republic of Colombia, is a country primarily located in South America with Insular region of Colombia, insular regions in North America. The Colombian mainland is bordered by the Caribbean Sea to the north, Venezuel ...

. A small portion of the fault runs through Huila. The fault has a total length of and runs along an average northeast to southwest

strike Strike may refer to: People *Strike (surname) * Hobart Huson, author of several drug related books Physical confrontation or removal *Strike (attack), attack with an inanimate object or a part of the human body intended to cause harm * Airstrike, ...

of 023 ± 4 in the

Central Ranges Central Ranges (code CER) is an Australian bioregion, with an area of 101,640.44 square kilometres (39,244 sq mi) spreading across two states and one territory: South Australia, Western Australia, and the Northern Territory.Andes The Andes ( ), Andes Mountains or Andean Mountain Range (; ) are the List of longest mountain chains on Earth, longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range ...

. The fault is active and associated with the deadly 1994 Páez River earthquake.

Etymology

The fault is named after ''vereda'' Irlanda of

Popayán Popayán () is the capital of the Colombian department of Cauca. It is located in the Pubenza Valley in southwestern Colombia between the Western Mountain Range and Central Mountain Range. The municipality has a population of 318,059, an a ...

, Cauca.Paris et al., 2000a, p.57

Description

The Irlanda Fault extends through the axis of the

Central Ranges Central Ranges (code CER) is an Australian bioregion, with an area of 101,640.44 square kilometres (39,244 sq mi) spreading across two states and one territory: South Australia, Western Australia, and the Northern Territory.Popayán Popayán () is the capital of the Colombian department of Cauca. It is located in the Pubenza Valley in southwestern Colombia between the Western Mountain Range and Central Mountain Range. The municipality has a population of 318,059, an a ...

. It cuts

igneous Igneous rock ( ), or magmatic rock, is one of the three main rock types, the others being sedimentary and metamorphic. Igneous rocks are formed through the cooling and solidification of magma or lava. The magma can be derived from partial ...

and

metamorphic rock Metamorphic rocks arise from the transformation of existing rock to new types of rock in a process called metamorphism. The original rock ( protolith) is subjected to temperatures greater than and, often, elevated pressure of or more, caus ...

s that are capped with

Quaternary The Quaternary ( ) is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS), as well as the current and most recent of the twelve periods of the ...

volcanic ash and

lapilli Lapilli (: lapillus) is a size classification of tephra, which is material that falls out of the air during a volcanic eruption or during some meteorite impacts. ''Lapilli'' is Latin for "little stones". By definition lapilli range from in dia ...

. The Irlanda Fault consists of two en-echelon strands. The fault trace has medium geomorphic expression and, although somewhat obscure, there are offset spurs, degraded fault scarps, broad fault valleys, saddles, aligned drainage, and deflected streams. The fault runs east of the Puracé

volcano A volcano is commonly defined as a vent or fissure in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most oft ...

and south of the

Nevado del Huila Nevado del Huila (, ) at , is the highest volcano in Colombia, located at the tripoint of the departments of Huila, Tolima and Cauca. It is visible from the city of Cali. The andesitic volcano is located on top of the Ibagué Batholith.Planc ...

.Paris, 2000b

Activity

The fault has been estimated as being responsible for the 1994 Páez River earthquake, occurring on June 6, 1994.Paris et al., 2000a, p.58 The earthquake happened at a depth of and had a

moment magnitude The moment magnitude scale (MMS; denoted explicitly with or Mwg, and generally implied with use of a single M for magnitude) is a measure of an earthquake's magnitude ("size" or strength) based on its seismic moment. was defined in a 1979 paper ...

of 6.8 and an intensity of VII. The earthquake destroyed the town of Páez and produced approximately 1100 fatalities.Olson et al., 1995, p.61 The Colombian Red Cross presented a figure of 28,000 people affected by the earthquake and the resulting landslides, mudflows, avalanches and isolation due to lacking communication.Olson et al., 1995, p.12

References

Bibliography

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Etymology

Description

Activity

See also

References

Bibliography

Maps

Further reading