Artículos Científicos

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https://hdl.handle.net/20.500.12748/591

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Mostrando 1 - 9 de 9

Modeling a glacial lake outburst flood process chain: the case of Lake Palcacocha and Huaraz, Peru
(Copernicus GmbH, 2016-07-01) Marcelo A. Somos-Valenzuela; Rachel E. Chisolm; Denny S. Rivas; Cesar Portocarrero; Daene C. McKinney
Abstract. One of the consequences of recent glacier recession in the Cordillera Blanca, Peru, is the risk of glacial lake outburst floods (GLOFs) from lakes that have formed at the base of retreating glaciers. GLOFs are often triggered by avalanches falling into glacial lakes, initiating a chain of processes that may culminate in significant inundation and destruction downstream. This paper presents simulations of all of the processes involved in a potential GLOF originating from Lake Palcacocha, the source of a previously catastrophic GLOF on 13 December 1941, killing about 1800 people in the city of Huaraz, Peru. The chain of processes simulated here includes (1) avalanches above the lake; (2) lake dynamics resulting from the avalanche impact, including wave generation, propagation, and run-up across lakes; (3) terminal moraine overtopping and dynamic moraine erosion simulations to determine the possibility of breaching; (4) flood propagation along downstream valleys; and (5) inundation of populated areas. The results of each process feed into simulations of subsequent processes in the chain, finally resulting in estimates of inundation in the city of Huaraz. The results of the inundation simulations were converted into flood intensity and preliminary hazard maps (based on an intensity-likelihood matrix) that may be useful for city planning and regulation. Three avalanche events with volumes ranging from 0.5 to 3  ×  106 m3 were simulated, and two scenarios of 15 and 30 m lake lowering were simulated to assess the potential of mitigating the hazard level in Huaraz. For all three avalanche events, three-dimensional hydrodynamic models show large waves generated in the lake from the impact resulting in overtopping of the damming moraine. Despite very high discharge rates (up to 63.4  ×  103 m3 s−1), the erosion from the overtopping wave did not result in failure of the damming moraine when simulated with a hydro-morphodynamic model using excessively conservative soil characteristics that provide very little erosion resistance. With the current lake level, all three avalanche events result in inundation in Huaraz due to wave overtopping, and the resulting preliminary hazard map shows a total affected area of 2.01 km2, most of which is in the high hazard category. Lowering the lake has the potential to reduce the affected area by up to 35 %, resulting in a smaller portion of the inundated area in the high hazard category.
Multi-Source Glacial Lake Outburst Flood Hazard Assessment and Mapping for Huaraz, Cordillera Blanca, Peru
(Frontiers in Earth Science, 2018) Instituto Nacional de Investigación en Glaciares y Ecosistemas de Montaña; Frey Holger; Huggel Christian; Chisolm Rachel E.; Baer Patrick; McArdell Brian; Cochachin Alejo; Portocarrero César; Frontiers in Earth Science
The Quillcay catchment in the Cordillera Blanca, Peru, contains several glacial lakes, including Lakes Palcacocha (with a volume of 17 x 106 m3), Tullparaju (12 x 106 m3) and Cuchillacocha (2 x 106 m3). In 1941 an outburst of Lake Palcacocha, in one of the deadliest historical glacial lake outburst floods (GLOF) worldwide, destroyed large parts of the city of Huaraz, located in the lowermost part of the catchment. Since this outburst, glaciers and glacial lakes in Quillcay catchment have undergone drastic changes, including a volume increase of Lake Palcacocha between around 1990 and 2010 by a factor of 34. In parallel, the population of Huaraz grew exponentially to more than 120,000 inhabitants nowadays, making a comprehensive assessment and mapping of GLOF hazards for the Quillcay catchment and the city of Huaraz indispensable. Here we present a scenario-based multi-source GLOF hazard mapping, applying a chain of interacting numerical models to simulate involved cascading mass movement processes. Susceptibility assessments for rock-ice avalanches and breach formation at moraine dams were used to define scenarios of different magnitudes and related probabilities, which are then simulated by corresponding mass movement models. The evaluation revealed, that (1) the three investigated lakes pose a significant GLOF hazard to the Quillcay Catchment and the city of Huaraz, (2) in some scenarios the highest hazard originates from the lake with the smallest volume (Cuchillacocha), and (3) current moraine characteristics of Lake Palcacocha cannot be compared to the situation prior and during the 1941 outburst. Results of outburst floods obtained by the RAMMS model were then converted into intensity maps and corresponding hazard levels according to national and international standards, and eventually combined into the GLOF hazard map for the entire Quillcay catchment, including the urban area of Huaraz. Besides technical aspects of such a multi-source model-based hazard mapping, special attention is also paid to approval and dissemination aspects in a complex institutional context. Finally, some general conclusions are drawn and recommendations are given, that go beyond the presented case of the Quillcay Catchment.
Landslide hazard assessment and risk reduction in the rural community of Rampac Grande, Cordillera Negra, Peru
(Springer Science and Business Media LLC, 2023-12-22) Jan Klimeš; Jan Novotný; Jan Balek; Ana Marlene Rosario; Juan C. Torres-Lázaro; Roque Vargas; Darwing López; Yeny Obispo; Edgardo Roldán-Minaya; Adriana Caballero; Harrinson W. Jara; Hilbert Villafane; Enver Melgarejo
This article describes the landslide risk assessment of the Rampac Grande rural community in the Peruvian Andes, where an unexpectedly fast-moving landslide claimed fatalities in 2009. The study site represents a socially, culturally, and geologically challenging environment that limits applicable technical solutions for landslide risk reduction and demands a high level of community participation in all risk reduction steps. The performed landslide surface movement monitoring and slope stability calculations showed that the studied slopes are very close to failure. Therefore, the detailed hazard assessment was combined with field investigations of household vulnerabilities to perform a qualitative risk assessment in the zone around the 2009 catastrophic landslide. Results show that the high vulnerability, rather than the very high hazard, is responsible for assigning houses to the high-risk classes and education or improvement of the households’ income is key for further risk reduction. This underlines the importance of vulnerability reduction through the collaboration of the community members with external actors (e.g., Peruvian experts), which was interrupted by the COVID-19 pandemic restrictions. The context of the performed landslide risk assessment provides a summary of the 12-year-long involvement of different actors in the landslide risk reduction effort and the evaluation of the effectiveness of the previously adopted mitigation measures. It suggests that the community perspective on the mitigation measures and its risk perception changes determine the long-term risk reduction outcomes.
Assessment of Human Health Risk Indices Due to Metal Contamination in the Surface Water of the Negro River Sub-Basin, Áncash
(MDPI AG, 2024-06-05) Walter Bravo-Zevallos; Yadira Fernández-Jerí; Juan C. Torres-Lázaro; Karol Zuñiga-Bardales
The accelerated loss of glacial cover in the Cordillera Blanca in Áncash, Peru, exposes the underlying rocks with high concentrations of sulfides from the Chicama Formation to oxidation and leaching processes, generating acid rock drainage (ARD) in glacial and periglacial areas. These are transported by surface runoff, contaminating the surface water with high concentrations of metals and sulfates, as well as increasing the acidity, which poses a risk to human health and the ecosystem. Therefore, the risk indices for human health due to metal contamination were evaluated at 19 surface water sampling points distributed in the Río Negro sub-basin. Hydrochemical analyses revealed average metal concentrations in the following order: Fe (28.597 mg/L), Al (3.832 mg/L), Mn (1.085 mg/L), Zn (0.234 mg/L), Ni (0.085 mg/L), Co (0.053 mg/L), Li (0.036 mg/L), Cu (0.005 mg/L), and Pb (0.002 mg/L). The risk was determined by calculating the Heavy Metal Pollution Index (HPI) and the Hazard Index (HI). The average HPI value was 360.959, indicating a high level of contamination (HPI ≥ 150). The human health risk assessment indicated that adverse effects caused by iron, lithium, and cobalt in children and adults should be considered. Through the use of Pearson correlation analysis, principal component analysis, and cluster analysis, it was identified that SO42−, Fe, S, Al, Co, Mn, Ni, Zn, and Li originate from natural sources, associated with the generation of ARD in glacial and periglacial areas.
The 2020 glacial lake outburst flood process chain at Lake Salkantaycocha (Cordillera Vilcabamba, Peru)
(Landslides, 2021-06-01) Vilca, Oscar; Mergili, Martin; Emmer, Adam; Frey, Holger; Huggel, Christian
Este estudio investiga la cadena de procesos que desencadenó una Inundación Repentina de Lago Glaciar (GLOF) en el lago Salkantaycocha, en la Cordillera Vilcabamba, Perú, el 23 de febrero de 2020. El evento comenzó con un deslizamiento de tierra en la ladera suroeste del Nevado Salkantay, que evolucionó hacia una avalancha de roca y hielo. El impacto de esta avalancha en el lago glaciar represado por morrena generó una onda de desplazamiento que sobrepasó y erosionó la presa morrénica, provocando el desbordamiento y un GLOF de gran magnitud. El aluvión resultante causó muertes y desapariciones en el valle río abajo. El análisis se basa en investigaciones de campo, datos de teledetección, meteorología y simulaciones computacionales con un modelo de flujo de dos fases, lo que permitió comprender tanto la dinámica del evento como las condiciones previas y posteriores al mismo, proporcionando valiosa información sobre la vulnerabilidad de los lagos glaciales en la región.
A new GLOF inventory for the Peruvian and Bolivian
(EGU General Assembly, 2019-04) Adam Emmer; Simon Cook; Joanne L. Wood; Stephan Harrison; Ryan Wilson; Alejandro Diaz-Moreno; John M. Reynolds; Juan Torres Lazaro
Este estudio presenta un nuevo inventario de inundaciones repentinas por desbordes de lagos glaciares (GLOF, por sus siglas en inglés) en los Andes del Perú y Bolivia, con el objetivo de evaluar cambios en su frecuencia y magnitud en el contexto del cambio climático. Ante la limitada disponibilidad de registros históricos, especialmente en regiones montañosas remotas, se emplearon imágenes satelitales y aéreas multitemporales de alta resolución, combinadas con fuentes documentales, para identificar y caracterizar más de 150 eventos GLOF. Este número supera significativamente los registros previos conocidos. El estudio proporciona estadísticas detalladas sobre la ubicación, magnitud, temporalidad y características de estos eventos, incluyendo descripciones de casos específicos y de las cadenas de procesos asociadas. Los resultados ofrecen una base sólida para futuras evaluaciones de peligros, estudios de atribución al cambio climático y estrategias de gestión del riesgo en ecosistemas de montaña.
Modelling the impact of a GLOF scenario at Parón lake, Cordillera Blanca, Perú, using a novel multi-phase topographical and geological procedure
(EGU General Assembly, 2021-04) Hilbert Villafane Gomez; Juan C. Torres Lázaro; Adriana Caballero Bedriñana; Harrinson W. Jara Infantes; Enver L. Melgarejo Romero; Julia E. Araujo Reyes; Christian Yarleque; Stephan Harrison; Ryan Wilson; Joanne L. Wood; Neil F. Glasser
Este estudio modela el impacto de un escenario de Inundación Repentina de Lago Glaciar (GLOF) en el lago Parón, ubicado en la Cordillera Blanca, Perú, utilizando un novedoso procedimiento topográfico y geológico de múltiples fases. La Cordillera Blanca ha experimentado un rápido deshielo impulsado por el cambio climático, lo que ha dado lugar a la formación de nuevos lagos glaciares y al aumento del volumen de lagos existentes, algunos de los cuales representan un peligro significativo debido al riesgo de GLOF. El lago Parón es uno de estos casos críticos, ya que su cercanía al glaciar Hatunraju lo hace vulnerable a las avalanchas de hielo, que podrían generar ondas de impulso capaces de iniciar la erosión de la presa morrénica natural. Según el modelo, en el peor de los escenarios, una avalancha de hielo podría hacer que el GLOF llegue a la ciudad de Caraz en 36 a 42 minutos, con tasas de inundación entre 11.2 m/s y 22.4 m/s, y alturas de inundación que fluctúan entre 9.9 m y 19.7 m. Este análisis proporciona una evaluación crucial de los riesgos asociados a GLOF y contribuye a la planificación de medidas de mitigación en la región.
DInSAR monitoring of glacier dynamics in Cordillera Blanca and Vilcabamba
(EGU General Assembly, 2021) Christian Riveros Lizana; Raul Espinoza Villar; Harrison Jara Infantes; Juan Carlos Torres Lazaro; Instituto Nacional de Investigación en Glaciares y Ecosistemas de Montaña
Este estudio aplica el análisis de Radar de Apertura Sintética Interferométrica Diferencial (DInSAR) utilizando datos del satélite Sentinel-1, con el fin de monitorear la dinámica glaciar en las cordilleras Blanca y Vilcabamba entre febrero de 2019 y marzo de 2020. Ante las limitaciones de los métodos convencionales y las imágenes ópticas, especialmente en zonas montañosas remotas con alta cobertura nubosa, el enfoque DInSAR permitió mapear desplazamientos y hundimientos en los glaciares. Estos resultados se integraron con datos de temperatura superficial y precipitaciones, lo que permitió generar estadísticas zonales y evaluar áreas asociadas a posibles peligros por inundaciones repentinas de origen glaciar (GLOF). El estudio ofrece una visión más precisa sobre los efectos del cambio climático en la dinámica de los glaciares tropicales y contribuye a la identificación de regiones vulnerables en los Andes peruanos.
Monitoring the Stability of a Moraine Dam by Differential Interferometry (DInSAR) to Prevent GLOFs Disasters from Arhuaycocha Lake
(International Conference on Sustainable Infrastructure, 2021-12-07) Christian Riveros Lizana; Raul Espinoza Villar; Harrison Jara Infantes; Juan Carlos Torres Lazaro; Instituto Nacional de Investigación en Glaciares y Ecosistemas de Montaña
Este estudio evalúa la estabilidad del dique morrénico de la laguna Arhuaycocha, ubicada en la Cordillera Blanca, mediante el uso de Interferometría Diferencial de Radar de Apertura Sintética (DInSAR), con el objetivo de prevenir desastres asociados a inundaciones repentinas de origen glaciar (GLOF). La Cordillera Blanca, reconocida como la cadena montañosa tropical con mayor concentración de glaciares en el mundo, ha experimentado una significativa reducción en su cobertura glaciar desde 1930, lo que ha generado la formación de numerosos lagos represados por morrenas. De los 230 lagos glaciares identificados en la región, 119 presentan este tipo de represa natural. Estos cuerpos de agua han incrementado el riesgo de GLOF, sobre todo cuando se ven afectados por movimientos en las laderas, como caídas de hielo, avalanchas y desprendimientos de roca. A través del monitoreo satelital con DInSAR, se busca detectar desplazamientos en las morrenas que puedan comprometer la estabilidad de los diques, permitiendo una evaluación temprana de posibles amenazas y contribuyendo así a una gestión más efectiva del riesgo en cuencas glaciares vulnerables.

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