The Ibagué Fault ( es, Falla de Ibagué) is a major dextral slightly oblique

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 Department may refer to: * Departmentalization, division of a larger organization into parts with specific responsibility Government and military *Department (administrative division), a geographical and administrative division within a country, ...

of Tolima in central

Colombia Colombia (, ; ), officially the Republic of Colombia, is a country in South America with insular regions in North America—near Nicaragua's Caribbean coast—as well as in the Pacific Ocean. The Colombian mainland is bordered by the Car ...

. The fault has a total length of and runs along an average east-northeast to west-southwest strike of 067.9 ± 11 cross-cutting 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 fault is part of a regional shear zone and has been active in historical times, possibly associated with the 1825 Ibagué earthquake and an earthquake in 1942.

Etymology

The fault is named after Ibagué, the capital of Tolima.Diederix et al., 2006, p.492

Description

The Ibagué Fault crosses the central part and eastern slope 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.Andes, close to the city of Ibagué. The fault strikes west-southwest to east-northeast, controlling the course of the Cocora River. The fault has a well developed fault trace with prominent linear fault ridges (whale backs) as much as long and high, fault scarplets aligned with ridges, sag ponds, fault-controlled drainage, tilted deposits and upwarping. There is about of (young) displacement along strike as calculated from a "whale back" offset by the fault.Paris et al., 2000, p.50 The fault, forming a series of ramps,Cuéllar Cárdenas, 2014, p.43 terminates at the Magdalena River, north of Guataquí.Plancha 245, 1999

Tectonic framework

The Ibagué Fault forms part with the Garrapatas and Cucuana Faults a shear zone between the latitudes 4 and 5 degrees north. To the north of this zone, regional structures are oriented along a north-northeast strike, characterised by sinistral displacement, among others the San Jerónimo, Silvia-Pijao, Cauca-Almaguer,

Murindó Murindó is a town and municipality in the Colombian department of Antioquia. Climate Murindó has a tropical rainforest climate A tropical rainforest climate, humid tropical climate or equatorial climate is a tropical climate sub-type usual ...

, Bituima-La Salina and Bucaramanga-Santa Marta Faults. The movement along these structures generates a transpressive tectonic regime, related to the collision of the Chocó Block in the west of Colombia, during the

Late Miocene The Late Miocene (also known as Upper Miocene) is a sub-epoch of the Miocene epoch (geology), Epoch made up of two faunal stage, stages. The Tortonian and Messinian stages comprise the Late Miocene sub-epoch, which lasted from 11.63 Ma (million ye ...

. To the south of the structural zone the Ibagué Fault belongs to, north-northeast striking faults are mostly dextral, such as the Buesaco-Aranda, Cali-Patía and Algeciras Faults. Those are produced by the oblique

subduction Subduction is a geological process in which the oceanic lithosphere is recycled into the Earth's mantle at convergent boundaries. Where the oceanic lithosphere of a tectonic plate converges with the less dense lithosphere of a second plate, the ...

of the Malpelo Plate, formerly considered belonging to the

Nazca Plate The Nazca Plate or Nasca Plate, named after the Nazca region of southern Peru, is an oceanic tectonic plate in the eastern Pacific Ocean basin off the west coast of South America. The ongoing subduction, along the Peru–Chile Trench, of the Na ...

with the continental margin of the

South American Plate The South American Plate is a major tectonic plate which includes the continent of South America as well as a sizable region of the Atlantic Ocean seabed extending eastward to the African Plate, with which it forms the southern part of the Mid-A ...

.Montes et al., 2004, p.14 The Ibagué Fault cross-cuts the central part of the Central Ranges and extends along a strike of approximately 070 to the east to the

Middle Magdalena Valley The Middle Magdalena Valley, Middle Magdalena Basin or Middle Magdalena Valley Basin ( es, Valle Medio del Magdalena, commonly abbreviated to VMM) is an intermontane basin, located in north-central Colombia between the Central and Eastern Ranges of ...

. Along its trace it principally cuts Paleozoic metamorphic rocks of the Cajamarca Complex, the Jurassic age

Ibagué Batholith Ibagué () (referred to as San Bonifacio de Ibagué del Valle de las Lanzas during the Spanish period) is the capital of Tolima, one of the 32 departments that make up the Republic of Colombia. The city is located in the center of the country ...

consisting of granodiorites, tonalites, granites, porphyrics of andesitic and dacitic composition and extrusive rocks as pyroclastic deposits and lava,Cuéllar Cárdenas et al., 2014, p.39

Paleogene The Paleogene ( ; British English, also spelled Palaeogene or Palæogene; informally Lower Tertiary or Early Tertiary) is a geologic period, geologic period and system that spans 43 million years from the end of the Cretaceous Period million yea ...

and

Neogene The Neogene ( ), informally Upper Tertiary or Late Tertiary, is a geologic period and system that spans 20.45 million years from the end of the Paleogene Period million years ago ( Mya) to the beginning of the present Quaternary Period Mya. ...

sedimentary rocks of the Gualanday and Honda Groups and displacing and deforming the

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). It follows the Neogene Period and spans from 2.58 million years ...

Ibagué Fan ( es, Abanico de Ibagué), which is of volcano-sedimentary origin.Montes et al., 2004, p.15 The fault passes southeast of the Nevado del Ruiz and

Cerro Machín Cerro Machín is a stratovolcano located in Tolima Department, Colombia. Cerro Machin is a volcanic plug that is approximately the same age (1,000,000+ years) as the Ruiz-Tolima Massif and has the appearance of being part of that volcanic system ...

volcanoes A volcano is a rupture 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 often found where tectonic plates are ...

.Montes et al., 2004, p.16Montes et al., 2004, p.17

Activity

A rate of per year is estimated and per year published,Diederix et al., 2006, p.502 based on deformed and offset Quaternary features and dated deposits. A calculated moment magnitude of 7.0-7.2 is based on most probable fault rupture length of about , from Ibagué to Piedras. The most recent movement is estimated at 1040 to 1280 AD on the basis of radiocarbon dated deposits.Montes et al., 2004, p.167 Two epicentres of historical earthquakes are located close to the fault, an earthquake of May 22, 1942 with magnitude 5.8 and an

intensity Intensity may refer to: In colloquial use *Strength (disambiguation) *Amplitude * Level (disambiguation) * Magnitude (disambiguation) In physical sciences Physics *Intensity (physics), power per unit area (W/m2) *Field strength of electric, ma ...

in Ibagué of VIII and the intensity VI 1825 Ibagué earthquake of January 1, 1825.Montes et al., 2004, p.18

Etymology

Description

Tectonic framework

Activity

See also

References

Bibliography

Maps

Further reading