Articles | Volume 15, issue 4
Nat. Hazards Earth Syst. Sci., 15, 757–766, 2015
https://doi.org/10.5194/nhess-15-757-2015
Nat. Hazards Earth Syst. Sci., 15, 757–766, 2015
https://doi.org/10.5194/nhess-15-757-2015

Research article 08 Apr 2015

Research article | 08 Apr 2015

Secondary lahar hazard assessment for Villa la Angostura, Argentina, using Two-Phase-Titan modelling code during 2011 Cordón Caulle eruption

G. Córdoba1, G. Villarosa2, M. F. Sheridan3, J. G. Viramonte4, D. Beigt2, and G. Salmuni5 G. Córdoba et al.
  • 1Universidad de Nariño, Pasto, Colombia
  • 2Universidad del Comahue, INIBIOMA, Bariloche, Argentina
  • 3SUNY University at Buffalo, Buffalo, NY, USA
  • 4Universidad Nacional de Salta, INENCO-GEONORTE-UNSa-CONICET, Salta, Argentina
  • 5Comisión Nacional de Actividades Espaciales, CONAE, Salta, Argentina

Abstract. This paper presents the results of lahar modelling in the town of Villa La Angostura (Neuquén-Argentina) based on the Two-Phase-Titan modelling computer code. The purpose of this exercise is to provide decision makers with a useful tool to assess lahar hazard during the 2011 Puyehue-Cordón Caulle Volcanic Complex eruption. The possible occurrence of lahars mobilized from recent ash falls that could reach the city was analysed. The performance of the Two-Phase-Titan model using 15 m resolution digital elevation models (DEMs) developed from optical satellite images and from radar satellite images was evaluated. The output of these modellings showed inconsistencies that, based on field observations, were attributed to bad adjustment of the DEMs to real topography. Further testing of results using more accurate radar-based 10 m DEM, provided more realistic predictions. This procedure allowed us to simulate the path of flows from Florencia, Las Piedritas and Colorado creeks, which are the most hazardous streams for debris flows in Villa La Angostura. The output of the modelling is a valuable tool for city planning and risk management especially considering the glacial geomorphic features of the region, the strong urban development growth and the land occupation that has occurred in the last decade in Villa La Angostura and its surroundings.

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This paper shows the results of secondary lahar modelling in Villa La Angostura town (Neuquén-Argentina) based on the Two-Phase-Titan modelling computer code. Possible occurrence of secondary lahars that could reach the city was analysed. The procedure allowed simulation of the path of flows from Florencia, Las Piedritas and Colorado creeks, which are the most influential streams in Villa La Angostura. The output of the modelling is a valuable tool for city planning and risk management.
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