Las Cañas rock-avalanche: Another manifestation of these phenomena on the western slope of the Sierra Grande de San Luis

• Autores: González Díaz, E.F.; Eauqué, L.; Costa, C.H.; Giaccardi, A.D.
• Año de publicación: 1998
• Idioma: inglés
• Tipo de recurso: artículo
• Fuente: Rev. Asoc. Geol. Argent. 1998;53(3):325-336
• Materia: avalanche; coseismic process; rockfall; seismic hazard; structural geology; Argentina
• Institución: Universidad Nacional de Buenos Aires. Facultad de Ciencias Exactas y Naturales

A rock-avalanche (named Las Cañas) was distinguished near the Potrero de Leyes rock-avalanche previously recognized in the southern Sierras Pampeanas. It is located on the western slope of the Sierra Grande de San Luis (San Luis Province), which is regarded as the range uplift front during the Andean tectonism. On account of its greater degradation than the Potrero de Leyes rock-avalanche, the deposits described here are considered to be older in age. Their morphometric attributes could be only roughly calculated, because fluvial erosion has removed a large portion of its initial shape and volume. The avalanche-related deposits form round-shaped hills, which can be distinguished from alluvial fan deposits by their higher altitude, photogeological signature and degree of degradation. Two fault sets have also modified its original surface configuration. It is considered that this phenomenon was also triggered by an earthquake. Hence, the recognition and analysis of these geomorphological processes provides a useful addition to palaeosismological analysis and is significant for an adequate evaluation of the the seismic hazard of this region. © 1998 Asociación Geológica Argentina.