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

Abstract

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 PuyehueCordón 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 TwoPhase-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.

The Geomorphology, Structure, and Lava Flow Dynamics of Peralkaline Rift Volcanoes From High‐Resolution Digital Elevation Models

“…The geomorphology of volcanoes has long been used to investigate volcanic development and activity (Thouret, 1999). Digital topography has been used to classify volcano morphology (e.g., Euillades et al, 2013;Favalli et al, 1999;Grosse et al, 2014;Pedersen & Grosse, 2014;Prima & Yoshida, 2010), identify and assess eruptive deposits and structures (e.g., Csatho et al, 2008;Hofton et al, 2006;Hutchison et al, 2015;Zouzias et al, 2011), and evaluate ongoing volcanic hazards (e.g., Favalli et al, 2005;Córdoba et al, 2015;Stefanescu et al, 2012). Many studies have used the morphometry of lava flow deposits (e.g., Nomikou et al, 2014;Pyle & Elliott, 2006;Tarquini et al, 2012;Ventura & Vilardo, 2007), cones (e.g., Fornaciai et al, 2012;Kervyn et al, 2012), and other deposits (e.g., Jessop et al, 2012) to investigate their rheology and dynamics of emplacement.…”

From examination of natural events to a proposal for risk mitigation of lahars by a cellular-automata methodology: a case study for Vascún valley, Ecuador

“…LLUNPIY, SCIDDICA-SS3, and SCIDDICA-SS2 are our most advanced models (in the sense that they include the features of the previous models plus other new ones) for simulating flow-like landslides and lahars. Unlike other models, which were used in lahar simulations (LAHARZ -e.g., Schilling, 1998;Muñoz-Salinas et al, 2009;TITAN2De.g., Sheridan et al, 2005;Williams et al, 2008;Córdoba et al, 2015), they allow the implementation of the erosion process.…”

A Modeling Approach for Lahar Hazard Assessment: the Case of Tamasagra Sector in the City of Pasto, Colombia

“…Titan2F was developed to account for both of the phases keeping a reasonable computational cost [8], [21]. The fluid part of the flow is modeled using typical shallow water like approach, whereas the frictional behavior of the solid phase is accounted by assuming that Mohr-Coulomb law is valid in such case, as in [17] and [18].…”

“…The modeling techniques range from empirical or semi-empirical models (see for example [3], [4]) to models that consider the mechanics of their behavior (e.g. [5], [6], [7], [8]). Each kind of model have its own strengths and weakness.…”

“…This study uses the computational program Titan2F [8] to investigate the path, the predicted flow depth and dynamic pressures that can be expected when typical lahar flows from Mijitayo creek reaches the city of Pasto. The sector of the city at which we apply the computational model Titan2F is known as Tamasagra, which covers several neighborhoods where there are almost 40.000 inhabitants ("Comuna" 7 and half of "Comuna" 6) that can be affected directly [9].…”