Filiación institucional de autor: Alejo Cochachín Rapre /Autoridad Nacional del Agua - Unidad de Glaciología y Recursos Hídricos (ANA-UGRH), Huaraz, Peru

Filiación institucional de autor: Alejo Cochachín Rapre / Autoridad Nacional del Agua - Unidad de Glaciología y Recursos Hídricos (ANA-UGRH), Huaraz, Peru

Original abstract: This paper presents results of a study on the mechanical properties of sandy and gravely soils within the Cordillera Blanca, Peru. The soils were divided into groups according to their origin (glacial, fluvial, or debris flow). The grain size distribution of forty three soil samples was used to classify the soils according to the scheme of the Unified Soil Classification System (USCS). These distributions have then been used to estimate shear strength and hydraulic properties of the soils. There are clear differences between the soils which reflect their divergent origins. The glacial soils normally fit within one of two distinctive groups according to the proportion of fines (Group A, 7%–21.5%; Group B, 21%–65%). The estimation of shear strength at constant volume friction angle and peak shear strength of the glacial sediments with low content of fines was made us...

Original abstract: This article deals with the 2010 glacial lake outburst flood (GLOF) which happened in the Chucchún Valley in the Cordillera Blanca (Peru). The volume of the ice and rock fall from Mt. Hualcán was estimated to be about 500,000 m3 and the detachment zone was identified between 5,450 and 5,600 m a.s.l. Basic landforms and processes (e.g. stream erosion, accumulation) were characterized by field investigation (2010 and 2011) as well as the rate of deglaciation using remotely sensed data (1948, 1962, 1970 and 2010). Two relatively independent parts of the Chucchún Valley were identified from the point of view of sediment flux: uppermost part of the catchment (4,192–3,575 m a.s.l.), where even fine-grained sediments were laid down, and the lower reaches up to the confluence (3,191–2,640 m a.s.l.), where valley bottom sediments were mobilised by the increased discharge...

Filiación institucional de autor: Alejo Cochachín Rapre /Autoridad Nacional del Agua - Unidad de Glaciología y Recursos Hídricos (ANA-UGRH), Huaraz, Peru

Filiación institucional de autor: Alejo Cochachín Rapre /Autoridad Nacional del Agua - Unidad de Glaciología y Recursos Hídricos (ANA-UGRH), Huaraz, Peru

Filiación institucional de autor: Alejo Cochachín Rapre / Autoridad Nacional del Agua - Unidad de Glaciología y Recursos Hídricos (ANA-UGRH), Huaraz, Peru

Original abstract: In this article we describe natural hazards associated with outburst floods of Palcacocha Lake and landslide events on the slopes of its moraine dam, in Cojup Valley, Cordillera Blanca (Peru). These events occurred in the last 70 years and some of them resulted in disasters, which strongly affected the city of Huar´as. Field investigations and reference expression hydrodynamic tests as well as archive satellite images and aerial pictures were used to describe the evolution of hazards connected with Palcacocha Lake. Expression hydrodynamic tests proved a high permeability of sandy gravels glacial sediments, which form the present-day lake dam. Seepage through the natural dam forming small ponds below the overflow spillways occurs. A retreat of the glacial tongue causing an increase of the lake volume and unloading of the slope toe areas are the most important recent pr...

Filiación institucional de autor: Alejo Cochachín Rapre / Autoridad Nacional del Agua - Unidad de Glaciología y Recursos Hídricos (ANA-UGRH), Huaraz, Peru