Application of the composite maps method for landslide susceptibility assessment and its potential use for other natural risk analyses

Abstract

Composite maps have previously been applied to paleogeographic reconstructions and as an aid to mineral exploration. However, because they can combine different criteria that are used in risk and feasibility assessment into a single map with equal or weighted input from all the parameters, decisionmaking can be optimized. The methodology is particularly suitable for the evaluation of landslide hazard and susceptibility assessment, as it can combine the unfavourable factors typically associated with mountainous terrains. Composite maps also have the potential to standardize prediction and prevention criteria for different areas. The methodology is described together with an hypothetical example and a real case study in Patagonia, the results of which are compared with a susceptibility analysis of the same area using stochastic methods.Keywords: Geological hazards; slope failure, landslide susceptibility. RESUMENLos mapas compuestos han sido aplicados previamente en reconstrucciones paleogeográficas y como apoyo a la exploración minera. Sin embargo, dado que pueden combinar en un solo mapa diferentes criterios que usualmente se utilizan en análisis de riesgo y factibilidad, otorgando igual o distinto peso a los distintos parámetros, la toma de decisiones se ve optimizada. La metodología es particularmente aplicable en la evaluación de susceptibilidad y amenaza de remociones en masa, ya que puede combinar factores desfavorables típicamente presentes en terrenos montañosos. Los mapas compuestos tienen el potencial de estandarizar las predicciones y criterios preventivos para distintas áreas. Esta metodología se describe en conjunto con un ejemplo teórico y un estudio de caso real en la Patagonia, cuyos resultados son comparados con análisis de susceptibilidad en la misma zona usando métodos estocásticos.Palabras clave: Amenaza Geológica; falla en las laderas; susceptibilidad a deslizamientos de tierra.Recibido el 22 de julio de 2013, aceptado el 2 de diciembre de 2013.

Factors controlling alpine glaciations in the Sierra Baguales Mountain Range of southern Patagonia (50º S), inferred from the morphometric analysis of glacial cirques

“…For the first time in a cirque morphometric analysis, a composite map methodology (Le Roux and Rust, 1989;Merriam and Jewett, 1989;Le Roux, 1997;Sepúlveda et al, 2013) was used to assist in the cirque characterization. This technique was originally designed for paleogeographic reconstructions and uranium exploration and is based on the combination of different parameters (characteristics of cirques in this case) into single, combined values, which are eventually plotted on a composite map.…”

Geohazards in the Fjords of Northern Patagonia, Chile

“…Landslide inventory: A photointerpretation of aerial photographs (1982, 1997, 1:20,000 and 1:70,000) and Google Earth was completed and validated by fieldwork. Landslides were identified by morphological evidence, according to the criteria of Náquira [45], Sepúlveda and Serey [30] and Sepúlveda et al [32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47] for fjord environments. Vegetated landslides were also identified that occurred in the past but at unknown dates.…”