The Rosas-Julumito Fault () is an

oblique Oblique may refer to: * an alternative name for the character usually called a slash (punctuation) ( / ) *Oblique angle, in geometry * Oblique triangle, in geometry * Oblique lattice, in geometry * Oblique leaf base, a characteristic shape of the ...

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 southwestern

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 ...

. The fault is part of the megaregional Romeral Fault System and 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 026.9 ± 7 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 associated with the

1983 Popayán earthquake 1983 saw both the official beginning of the Internet and the first mobile cellular telephone call. Events January * January 1 – The migration of the ARPANET to TCP/IP is officially completed (this is considered to be the beginning of the ...

that partially destroyed

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 ...

, the capital of Cauca, and led to more than 300 fatalities. A maximum moment magnitude earthquake of 6.8 is estimated for the fault.

Etymology

The fault is named after Rosas, Cauca and vereda Julumito of Popayán.Paris et al., 2000a, p.24

Description

The Rosas-Julumito Fault is part of the Romeral Fault System. It is a rather short section of about length, of which have active tectonic movement. The fault section parallels the Cauca-Almaguer Fault, which is one of the largest older fracture zones in western Colombia. The Rosas-Julumito fault runs about west of the city of

. The fault crosses the

Pliocene The Pliocene ( ; also Pleiocene) is the epoch (geology), epoch in the geologic time scale that extends from 5.33 to 2.58Pleistocene The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...

Popayán Formation, which consists of

pyroclastic flow A pyroclastic flow (also known as a pyroclastic density current or a pyroclastic cloud) is a fast-moving current of hot gas and volcanic matter (collectively known as tephra) that flows along the ground away from a volcano at average speeds of b ...

mud flow A mudflow, also known as mudslide or mud flow, is a form of mass wasting involving fast-moving flow of debris and dirt that has become liquified by the addition of water. Such flows can move at speeds ranging from 3 meters/minute to 5 meters/se ...

and ash-fall deposits. It is believed that either the Rosas Fault or the nearby Julumito Fault (less than to the west) produced the earthquake of March 31, 1983 that partially destroyed the city of Popayán. The fault section runs through the smooth but hilly topography that is formed by sediments of the Popayán Formation. The fault morphology is easily observed in aerial photographs and satellite images and from aircraft. The most noticeable features are fault saddles, ponded

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 ...

alluvial Alluvium (, ) is loose clay, silt, sand, or gravel that has been deposited by running water in a stream bed, on a floodplain, in an alluvial fan or beach, or in similar settings. Alluvium is also sometimes called alluvial deposit. Alluvium is ...

valleys, stream deflections, offset drainages, linear fault ridges, and shutter ridges. Beyond the Popayán Formation, where the fault is in older rock formations, the topographic expression of the fault is still noticeable.

Activity

The fault is associated with the devastating 1983 Popayán earthquake (M_w 5.5) that caused more than 300 fatalities. During the 1983 earthquake, several cracks with generally north trends developed at the surface in an area wide and long, north of Popayán. Individual cracks were a few meters to tens of meters long and a few millimeters in width. A maximum

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 is assumed for this fault using only for its probable total

surface rupture In seismology, surface rupture (or ground rupture, or ground displacement) is the visible offset of the ground surface when an earthquake rupture along a Fault (geology), fault affects the Earth's surface. Surface rupture is opposed by buried rup ...

length.

Etymology

Description

Activity

See also

References

Bibliography

Maps

Further reading