West of the city of Mendoza, the Andes reach their highest elevation in the summit of Cerro Aconcagua. Directly south of Aconcagua, two major valley have been incised into the terrain of alpine type: the valley of the Río Mendoza on the Agentine side, and the Aconcagua Valley on the Chilean side, connected by a relatively low and easy-to-cross mountain pass, which has already been used by the national heroes of the early 19th Century. Still in the early 21st Century, the most important traffic link between Argentina and Chile runs along the same line: the Trans-Andean Corridor Mendoza - Valparaíso, which is part of the Corredor Bioceánico. The geomorphological diversity along this route is tremendous. However, the steep terrain also bears some landslide hazards, affecting traffic from time to time.
Click on the red symbols to visit the corresponding points of interest.
The Andes west of Mendoza in 3D
You can view this scene from various perspectives. Use the left mouse key to rotate, the mouse wheel to zoom, and the right mouse key to drag the scene.
In principle, the Andes consist of three parallel ranges at this latitude: the Precordillera Mendocina in the east is the geologically oldest among all of them. It is separated from the more than 6000 m high Cordillera Frontal by the Uspallata Valley, a tectonic graben. West of the Cordillera Frontal, Cerro Aconcagua is part of the Cordillera Principal. This range drops steeply towards west, resulting in a clearly asymmetric profile of the Andes.
This scene was generated with the QGIS plugin Qgis2threejs and uses the following libraries: three.js http://threejs.org/ (LICENSE) and Proj4js http://trac.osgeo.org/proj4js/ (LICENSE). Background: Bing Aerial.
What does this photograph want to tell us?
This image was taken close to Las Cuevas at more than 3100 m asl.
First, describe the photograph, and then find a suitable story for its content!
The image shows an abandoned railway line close to a station. The cover of the rails, only the remnants of which can be seen, served a a refuge for the trains in cases of heavy snowfall or too much snow on the tracks.
But how long was this railway line in service, and why was it abandoned at the end?
Stella will now tell you the background of the termination of railway traffic. Start the movie by clicking on the arrow.
Stella has done a lot of research on geomorphic processes in the valley of the Río Mendoza for more than one decade, and on the consequences of these processes on traffic. She is the major expert in this field.
But is it really the risk related to debris flows, slides, or rock fall, which has brought railway traffic to an end?
Movie: Peter Mathis and Gregor Offenthaler | Speaker: Stella Moreiras
The track was in service from the 19th Century to the end of the 20th Century. Passenger transport was suspended in the 1980s, and finally the transport of goods came to an end in the 1990s, when traffic was completely moved to the road. There are plans for the revival of railway traffic and the construction of a long base tunnel - however, these plans have not been realized until the early 21st Century. When visiting the individual points of interest along this trans-Andean corridor you will repeatedly encounter the remanants of the railway line - e.g. at Guido or at the Arroyo Seco. Since its abandonment - and lacking maintenance - it has been strongly affected by various hazardous processes and deterioration of the construction material. The damaged facilities may even put road traffic at risk, as it was the case downslope from Portillo.
Natural hazards along the Trans-Andean Corridor
First, visit the individual points of interest along the Trans-Andean Corridor, and learn which types of landslide processes are or were most important in which places. Then, assign the individual clips to the corresponding points in the map.
Grab the animation at the upper left symbol, and drag the symbol into the corresponding circle in the map.
Arroyo Seco: in 2016, a debris flow destroyed both the road bridge and the railway bridge.
Guido: not only the rock fall shown in the clip, but also debris flows affect the road from time to time, disrupt traffic, and sometimes even result in fatalities.
Las Cuevas: the rock avalanche from Cerro Tolosa fortunately happened a long time before the railway line and the road were put into service.
Portillo: Meltwater, which had collected in an abandoned railway tunnel, drained suddenly from the damaged tunnel, entrained some material on its way down, and affected the road below through a debris flow.
Abele, G. (1984). Derrumbes de montaña y morrenas en los Andes chilenos. Revista de Geografía Norte Grande 11: 17-30
Caviedes, C. (1972). Geomorfología del Cuarternario del valle del Aconcagua, Chile Central. Freiburger Geographische Hefte 11: 153 Seiten
Hauser, A. (2000). Flujos detríticos en segmento del Camino Internacional a Argentina, sector Juncal - Paso Los Libertadores: Causas, efectos, medidas de control. Bericht des Servicio Nacional de Geología y Minería, Subdirección Nacional de Geología, Santiago de Chile. 14 Seiten
Moreiras, S.M. (2004): Landslide incidence zonation in the Rio Mendoza valley, Mendoza province, Argentina. Earth Surface Processes and Landforms 29(2): 255-266 [Access source]
Moreiras, S.M. (2005): Landslide susceptibility zonation in the Rio Mendoza valley, Argentina. Geomorphology 66(1-4): 345-357 [Access source]
Moreiras, S.M. (2005): Climatic effect of ENSO associated with landslide occurrence in the Central Andes, Mendoza province, Argentina. Landslides 2(1): 53-59 [Access source]
Moreiras, S.M. (2006): Frequency of debris flows and rockfall along the Mendoza river valley (Central Andes), Argentina: Associated risk and future scenario. Quaternary International 158(1): 110-121 [Access source]
Moreiras, S.M., & Sepúlveda, S.A. (2015). Megalandslides in the Andes of central Chile and Argentina (32°-34° S) and potential hazards. Geological Society, London, Special Publications, 399(1), 329-344 [Access source]
Wikipedia article on the Transandine Railway [Access source]
This contribution was revised, extended, and translated from German by Martin Mergili.