Expansion of Moraine-Dammed Glacial Lakes and Historical GLOF Events in Cordillera Blanca Region of Peruvian Andes

摘要

The dramatic mass loss of Tropical Andean glaciers under the influence of climate change has caused alterations in regional hydrological regimes, including development and expansion of glacial lakes, especially moraine-dammed lakes, supraglacial lakes and ice-dammed lakes. There is a broad consensus on Moraine-Dammed Glacial Lakes (MDGLs) to be commonly understood as potentially most dangerous lakes that can trigger Glacial Lake Outburst Floods (GLOFs). The GLOF event in that process is expected to negatively impact the downstream communities, agricultural assets and infrastructure. In this study, we have prepared an updated and detailed inventory of MDGLs in the Cordillera Blanca region of the Peruvian Andes. The multi-temporal satellite data (TM, ETM, OLI and Sentinel-2A) was used to analyze the changes in lake area over a period of 40 years from 1980 to 2020. A total of 38 MDGLs (size > 0.05 km(2)) covering an area of 10.30 km(2), and located in the altitudinal zone ranging from 4155 to 4960 masl were identified and mapped. From 1980 (6.59 km(2)) to 2020 (10.3 km(2)), an expansion of 3.7 km(2) (35%) at an annual rate of 0.09 km(2)/year was observed in the lake area. This study also contributes in terms of developing a database of past GLOF events from an extensive literature survey to understand the hazard and disaster profile of the region for the period 1702-2020. A total of 28 GLOF events have been reported in the region which brought devastation to the surrounding communities. We conclude that the region is highly prone to GLOFs as understood from the occurrence of GLOFs in the past as well as from the current scenario of MDGLs.